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Hi. We've been working on a couple of interesting projects over at SC-3000 Survivors, and Bock suggested we might like to share our progress with everyone at SMS Power.

EDIT: see http://sc3000-multicart.com for progress updates on the Mk II Multicart. If you want to buy one, we are shipping now although there are only a few unreserved PCBs left. You can also find a tutorial on how to build your own 32-n-1 DIP switched based Multicart using only spare change, a shoe-lace and a swiss army knife ;)

Note also that this Multicart is for the SC-3000 ONLY. It does not work on the SG-1000, SG-1000 II, or Sega Mark III even though it plays all the known SG-1000 ROMs, and many of the recent Korean / Taiwanese releases that run in legacy mode.

I've built a multicart for the SC-3000 / SG-1000 system. It has been through a variety of iterations from breadboards to the current PCB based cart over the past year. It has a joystick / keyboard driven menu system and currently contains around 60-70 games including seventeen SC-3000 tape games that have been converted to load off the Multicart. Check out the video clip. One of my daughters shot the footage on my iPhone. She's only 5, so some of it is a little bit like the Blair Witch project, sorry :)

The multicart can run any 32KB, 16KB, or 8KB SC-3000 or SG-1000 ROM, so I won't say much about those. The only ROMs that require minor tweaks are Yie Ar Kung Fu and Konami Ping Pong. Those are MSX ports from the Taiwanese Aaronix console (SG-1000 clone). To get those to work on an SC-3000 you have to explicitly select the Joystick column of the keyboard matrix. So the multicart does that before paging those games into memory.

Yie Ar Kung Fu also needs a couple of mods to run with 32KB of RAM. When they ported it from the MSX code they missed a couple of memory locations, so there are 3 or 4 references hard coded to the $e000 range instead of $c000. That works fine with the 2KB of onboard RAM because the SC-3000 mirrors the onboard RAM. But it causes some interesting problems if your cart has 32KB of RAM :) So I patched those locations and it runs fine with 32KB of RAM now.

Current tape game list:

I just want to say a big thank you to everyone who has supported SMS Power over the years and made it the place it is today. This is the first major post I've made, but I've been a regular reader of the forums over the past couple of years and it is a nice place to hang out :)

In particular I'd like to mention the following SMSPower resources which were critical at various times during the build:

Thanks guys :)

I still have a fair bit of work to do on the software side. There are another 5-10 tape games I want to convert, and I've been doing things like putting some EPSGMOD files on there, a title screen, a simple audio digitizer / recorder utility (the SC-3000 can record 1-bit audio though the cassette-in port for use in games) etc. But it is getting there. I think I should be done by Christmas.

Note - at this stage this is just a prototype hobby cart and I've been building it for fun. Because the PCB design uses EPROMs, it contains copyrighted software when it is shipped. So I'm not sure if we'll ever be able to sell it in its current form, which is a shame because it is a pretty cool piece of kit. You just plug it in and away you go - no configuration required. But I'd welcome any thoughts on that.

I'll stick up some technical specs and a bit more info about how it works and why I made certain design choices in a future post.

By the way - I have a mostly completed tutorial for how to build your own 32-n-1 DIP switch based SC-3000 / SG-1000 Multicart if anyone is interested.

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The assembled SC-3000 Survivors Mk II Multicart

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Multicart PCB - Side B (top). Futurlec did a nice job.

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10 PCBs as shipped by Futurlec - just like a deck of cards. Surprisingly heavy - must be lots of lead in the solder :)

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The original 32-n-1 Mk I DIP Switch based Multi-cart (Jan/Feb 2011)

This is really cool! One of the best homebrew things I've seen in a while, and the PCB looks to be of quite high quality. What software did you use to design it that Futurelec accepts? Eagle?

About the copyrighted content, I think you could sell the PCB with an EPROM socket and let the user be responsible for supplying a chip and programming it. If you support Flash as well this may help more people as those chips are quite commonplace, cheap (29EE010/29F010, etc.) and a lot of people have device programmers but may not have an EPROM eraser.

To make the product immediately usable, you could include a programmed EPROM that has just your menu program and some freeware/homebrew games that would be legal to distribute, and it would be up to the users to then erase and reprogram that part with copyrighted game data (that they've dumped from their own cartridge collection, of course :)

Charles MacDonald wrote

This is really cool! One of the best homebrew things I've seen in a while, and the PCB looks to be of quite high quality. What software did you use to design it that Futurelec accepts? Eagle?

Hi Charles. Thanks for that, much appreciated.

I actually used ExpressPCB to design the PCB. Learning to draw a reasonably complex PCB from scratch is a *lot* of work and most of the PCB drawing programs I looked at were too hard to figure out with my limited knowledge at the time. ExpressPCB is really easy to use, and they have an excellent FAQ on the main things you need to get right when designing a PCB. They also have what looks like a very good automatic online ordering service where you can submit your design direct from the program and it will quote the price for you. And they ship quickly too. So all in all it looks like an excellent service especially if speed is important to you and you're based in the USA.

The downside of course is that you are locked into a proprietary format as you really have to place your order through them. I was fine with that originally as they had a reasonable price for their prototype boards (no solder mask layer). But when I went to order I discovered that they only do premium shipping. That is only like $10 in the US, but since I'm in New Zealand it was something like $80 - ie. almost half the price of the order. That annoyed me, so I asked them if they could stick it on slow post but they didn't reply.

So I hunted around various forums looking for how to convert ExpressPCB files. There are a few hacks, but it looked like a real pain so I even started to rebuild the design in Eagle.

But then I discovered that Futurlec will accept ExpressPCB files. It took about 6 weeks from when I first contacted them. 1 week to place the order and confirm the layout. 3.5 weeks to manufacture, 1.5 weeks to ship. But they were inexpensive, and did all the soldermask and silk-screening which is what makes it look so good.

I suspect they did the conversion the same way I'd read about in the forums. I think they used the ExpressPCB program to print out templates to PDFs or similar and then they manually made up masks and drilling files for each part of the process from that. Excellent value for the price, but some poor guy in Thailand is probably being paid $1 a day to do it by hand :)

I've had a look at Eagle now and I would probably use that in future to give myself the most flexibility when it came to manufacturing. But for ease of use I still recommend first time home-brewers give ExpressPCB some consideration whilst they are learning the ropes.

Charles MacDonald wrote

About the copyrighted content, I think you could sell the PCB with an EPROM socket and let the user be responsible for supplying a chip and programming it. If you support Flash as well this may help more people as those chips are quite commonplace, cheap (29EE010/29F010, etc.) and a lot of people have device programmers but may not have an EPROM eraser.

Good suggestions, thanks, and I'll look at them in more detail.

From memory, Flash memory has different pinouts to the EPROMs on the last few address pins once you go beyond the smaller sizes so I doubt I could do a straight substitution without rewiring. I'll take a look at that though.

This design uses the two 8MBit EPROMs which is about the largest size you can easily program with a cheap chinese programmer (approx $50USD on eBay), and which is easily pin compatible with the Z80 address and data lines. That gives you 64 slots of 32KB with my simple paging system. It will work fine with smaller capacity chips, but you halve the amount of games you can store every time you drop down a size (eg. to 4MBit). I'll write a bit more about that soon.

Charles MacDonald wrote

To make the product immediately usable, you could include a programmed EPROM that has just your menu program and some freeware/homebrew games that would be legal to distribute, and it would be up to the users to then erase and reprogram that part with copyrighted game data (that they've dumped from their own cartridge collection, of course :)

:) I'm just not sure how many people would actually bother simply because the SC-3000 was such a niche product so it has correspondingly less die hard fans than something like the Master System. And one of the neatest parts of the design is the copyrighted pre-packaged tape games, which you would lose. But yes, I'll look at that as a possibility, thanks.

Charles MacDonald wrote

About the copyrighted content, I think you could sell the PCB with an EPROM socket and let the user be responsible for supplying a chip and programming it. If you support Flash as well this may help more people as those chips are quite commonplace, cheap (29EE010/29F010, etc.) and a lot of people have device programmers but may not have an EPROM eraser.

Yes, that should work. I've had a look at the pinouts, and the only relevant differences are pins 1 (=A19 on the 27C801 EPROM and =A18 on the AM29F040) and 31 (=A18 on the EPROM and = WE on the Flash part). That section (the 5 highest address lines A15-A19) is all controlled by the 8 bit latch, so a Flash chip should plug straight in fine. I'd just have to rewrite the paging commands in the menu system to keep pin 31 low if you're using a Flash chip instead of an EPROM.

So the only downside is that halving of capacity as the largest Flash chip in a DIP 32 package is 4MBit. But with two 4MBit chips you would still get 32 slots of 32KB. Cool idea, thanks. I'll get myself some of those at some stage to play around with.

This is fantastic! I don't know what else to say, really, except that it's the kind of project one hopes someone might do someday -- but it's quite another thing to see it up and running. :)

BTW on the copyright issue, there are other highly visible multicarts that come preloaded with games and that, so far, haven't attracted any ugly attention. Since the SC-3000 is a pretty thoroughly abandoned system, it's less likely to get hassled than, say, the ColecoVision. (I think the guy who made a multicart for that system was indeed served with a C&D or something similar -- which is strange, actually: I wonder who owns the copyrights to those games?)

Do any of the games have NTSC/PAL compatibility issues? And will the SG-1000 side of things run on a Japanese SG-1000, or a Dina 2-in-1?

I'd love to see my Chack'n Pop translation running on real hardware! (Ninja Princess, not so much...)

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Yes, that should work. I've had a look at the pinouts, and the only relevant differences are pins 1 (=A19 on the 27C801 EPROM and =A18 on the AM29F040) and 31 (=A18 on the EPROM and = WE on the Flash part). That section (the 5 highest address lines A15-A19) is all controlled by the 8 bit latch, so a Flash chip should plug straight in fine.

Ah, I was thinking more along the lines of adding jumpers to the PCB (assuming there's room) to select between an EPROM or Flash pinout so the software could remain unchanged.

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So the only downside is that halving of capacity as the largest Flash chip in a DIP 32 package is 4MBit. But with two 4MBit chips you would still get 32 slots of 32KB.

Oh, I thought you were using aplib to compress the game images before decompressing them to RAM. Any reason why you aren't, like a performance issue? (Maybe it makes game loading too slow?)

goldenband wrote

This is fantastic! I don't know what else to say, really, except that it's the kind of project one hopes someone might do someday -- but it's quite another thing to see it up and running. :)

Thanks. It has been lots of fun but one hell of a learning curve :)

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BTW on the copyright issue, there are other highly visible multicarts that come preloaded with games and that, so far, haven't attracted any ugly attention. Since the SC-3000 is a pretty thoroughly abandoned system, it's less likely to get hassled than, say, the ColecoVision.

True. The Vic20 Megacart is the closest parallel I've seen to what I'd like to do. I see they've offered to give all their profits (if any) to charity which may help. Still - actually going ahead and doing it feels a bit like asking for a lightning bolt to come out of the sky :)

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Do any of the games have NTSC/PAL compatibility issues?

Not really. The SC-3000 / SG-1000 cartridge games were almost all timed to run on an NTSC system. There was no difference in the code distributed to PAL countries, so the only practical difference is that the games run about 10-15% slower on a PAL system because they only have 50 VBLANK interrupts per second instead of 60. Anyone brought up in NZ gets a bit of a shock the first time they try to play the games on an NTSC system and everything runs faster.

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And will the SG-1000 side of things run on a Japanese SG-1000, or a Dina 2-in-1?

I *assume* so. I only have NZ / PAL SC-3000s here to test on. Once I've tweaked the software a bit more I'll send some of the prototypes out to friends to try on different systems, if they have them.

The SC-3000 / SG-1000 games did not have SDSC tags in the header, so I assume this cart will work fine on a Sega Mk III. I'm not familiar with the Dina 2-in-1 (edit - just looked it up http://www.videogameconsolelibrary.com/pg80-dina.htm ).

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I'd love to see my Chack'n Pop translation running on real hardware! (Ninja Princess, not so much...)

Actually, I really liked the Ninja Princess translation :) The Chack ' n ' Pop translation runs fine too - I'm pretty sure I've tried that one out.

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Oh, I thought you were using aplib to compress the game images before decompressing them to RAM. Any reason why you aren't, like a performance issue? (Maybe it makes game loading too slow?)

:) I must finish off that technical overview. Oh well - no time like the present.

This is just the direction I came from initially. Take a look at that first DIP switch based multi-cart picture and you'll see what the thinking is. I was learning this stuff as I went and this was a natural way to build it using 1980s style technology. You could have built this multicart PCB design in 1984 (apart from the lack of the 8MBit EPROMs). It just uses 5v TTL logic to select from multiple 32KB blocks within the EPROMs.

The design process ran something like this.

The SC-3000 has a relatively small number of known ROMs (approx 80-90 games carts). Any one person can probably pick a list of 20-30 favourites they like and forget about the rest as they won't play them more than once. So it was possible to build a single cart that could contain most of the games I ever wanted to play. It later turned out I'm greedy and I wanted more than 30 games on the cart :)

The game ROMs are all 32KB or smaller (16KB / 8KB). And the SC-3000 is naturally set up for having the ROM in the lower 32KB of memory, and the RAM in the upper 32KB - either 2KB from C000 to C7FF or 16KB or 32KB with the Basic carts. And there are no known SC-3000 carts that use a paging system - that started with the Master System.

So the original paging system was based around just swapping out the lower 32KB of memory space and either using the on-board SRAM, or supplying your own.

I always envisaged using an 8-bit latch for this. But the original proof of concept was using a DIP switch.

For the Mk I multicart I desoldered a ROM off a Yamato cart. Then I soldered a 32 pin socket onto the original 28 pins. The highest 5 address lines on the 32 pin socket are hard wired to a DIP switch. That manipulates A15 to A19 on the 8MBit EPROM. So depending on the position of the DIP switches, you select a different logical 32KB block within the 8MBit EPROM. The lower 15 address lines A0 to A14 are all hardwired to the A0 to A14 pins on the EPROMs. You then turn on the computer, and it is just as if a different cart had been plugged in.

There are some obvious extensions to this, including using a 6th pin on the DIP switch wired to A14 through an OR gate so that either the Z80 A14 line OR the DIP switch can set A14 high. That gives you 16KB paging blocks. I've tried that and it works fine. That is actually handy because there are ummm... something like twenty two 16KB or 8KB ROMs, so you can pack more in. Unfortunately I ran out of room on the PCB (and time and patience, it has to be said), to do 16KB pages on the first PCB prototype. However I have left one bit of the 8-bit latch free to try this as a future mod.

I built and tested all this stuff on breadboards and I had to learn as I proceeded since my starting knowledge was reasonably close to zero :)

The PCB version uses a 74LS373 8-bit latch in place of the DIP switch. This is connected to the SC-3000 I/O bus on port $e0. The $e0 to $ff range is used by the SF-7000, so I knew this range would be clear of interference. After reading your hardware notes I knew there could be unpredictable behaviour if I put it lower even if it wasn't on one of the 'known' SC-3000 ports.

The PCB also has 32KB of SRAM. This is mapped at $8000 to $FFFF, just like the Basic IIIB cart.

So it is also perfectly suited to running tape games. Those always run in the upper 32KB of RAM and expect to have the IIIB ROM in the lower 32KB. I just need to write a custom loader for each one to load from the multi-cart paging system instead of calling the tape load routines. Single-load tape games are easy. You just copy the data to $9800, reset the basic pointers at $8160, and jump into the basic RUN entry point.

Multi-load games with seperate title screens etc. are harder and need the custom load treatment. But apart from loading from the multi-cart, the games load in the same sequence they did when loaded from tape, which is kind of neat.

So the ROMs are all uncompressed which makes for a nice simple hardware design with a very basic paging system. Where I have been using compression is in the loading of tape games. Those *are* copied into the top 32KB of RAM, so some of those are compressed to save space. Plus I've been playing around with digitized photos and music files etc. so the aPLib compressor is very handy for that.

The main components of interest on the PCB are:

The 74LS373 8 bit latch does 3 things:

The Reset switch behaviour is interesting. Unfortunately the SC-3000 does not pass the Z80 reset line out to the cartridge port. So the hard reset switch on the multicart disables the 8 bit latch which selects the last slot on the second ROM because the 74LS373 has internal pull up resistors. This is where the boot menu goes. You then press the Reset button on the SC-3000 keyboard which triggers the Reset handler in the boot menu block which basically returns back to $0000, cleans up the system, and displays the boot menu.

I have subsequently learned about other ways I could have built the cart. But I actually really like the 'old skool' design, and the TTL components are like old friends :)

Off in the distant future I have some vague plans for something using a more modern design, but hopefully the above explains where I've come from and how we ended up here.

CompletedCart_InCase01.JPG (64.89 KB)

32-n-1 Mk I Multicart - I removed the ROM from a Yamato cart, and added a 32 pin socket and DIP switch

you're a genius that is absolutely amazing stuff! I must congratulate you on such an awesome job. and was great to finally got to see Delta Fighter and Caverns of Karanor in action - brilliant! the quality is levels above most of the more common locally produced AU/NZ software and a refreshing change from the mass of arcade games released on cartridge. I'd definitely be interested in your tutorial of how to make one, also where do you buy the multicart PCB from? sent pm

Shroo-man wrote

I'd definitely be interested in your tutorial of how to make one

Hi All.

I've finally tidied up most of my draft SC-3000 multicart notes into a website:

http://sc3000-multicart.com

Check out the tutorial at http://sc3000-multicart.com/section1.htm that shows you how to build your own 32-n-1 SC-3000 / SG-1000 multicart by adding a DIP switch to an existing cart.

The tutorial is quite detailed and was inspired by the excellent SMS Reader tutorial. The DIP switch based cart isn't as nice as the Mk II boot menu version, but it is still pretty cool and it is reasonably easy to make yourself.

So have a go, and let me know how you get on :)

Hi All

Has anyone run into this before?

I'm trying out Charles' suggestion of using Flash / EEPROMs in the multicart. I bought some AM29F040B (4MBit Flash) DIP32 chips off eBay, but I'm having trouble programming them.

The chips are showing as all FF when first used, but the first write tends to have intermittent errors, and the Erase / Blank operations on my EPROM programmer just return errors so I can't easily wipe and overwrite them.

My EPROM programmer is a Top853 and is one of the cheapest you can buy on eBay. It has AM29F040 in its supported list, but not AM29F040B. Later revisions of this programmer (like the Top2004 and later) have the AM29F040B explicitly listed as well as the AM29F040. And being a cheap chinglish programmer documentation is almost non-existent.

Looking at the datasheets for both chips, there doesn't seem to be too much difference, so I'd have hoped they were write compatible. The AM29F040B datasheet says:

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This device is manufactured using AMD’s 0.32 μm process technology, and offers all the features and benefits of the Am29F040, which was manufactured using 0.5 μm process technology. In addtion, the Am29F040B has a second toggle bit, DQ2, and also offers the ability to program in the Erase Suspend mode.

Any thoughts anyone? I don't really want to buy another programmer as it works just fine on the ST27C801 EPROMs I've been using up to this point.

Or could the chips be faulty? I've tried two out of the 5 so far. They have a 1998 date stamp, and are supposed to be new. The pins were still in their 'wide' configuration, so it doesn't look like they've been socketed before.

Ta.

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My EPROM programmer is a Top853 and is one of the cheapest you can buy on eBay.

I have the Top853 too and it works with the AM29F040, though I can't recall if I used a "B" part specifically.

I have used AM29F040 and AM29F040B's interchangeably in the past with a different programmer that only supported the AM29F040, and it could erase, program, and verify the "B" parts just fine. So I agree that that are no major differences between the two.

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Or could the chips be faulty? I've tried two out of the 5 so far. They have a 1998 date stamp, and are supposed to be new. The pins were still in their 'wide' configuration, so it doesn't look like they've been socketed before.

Did you get these from eBay by any chance?

I've had a lot of problems in recent time with bad chips from Chinese eBay sellers -- parts that sound suspiciously like yours (chips that look new and are hard to program and erase consistently or at all)

I'd stick to official distributors if you can manage -- anyone listed at findchips.com or octopart.com is usually a safe bet. These days the 29F040 is harder to get and most DIP flash is 29F010 and 29EE010 which is only 128K.

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Did you get these from eBay by any chance? I've had a lot of problems in recent time with bad chips from Chinese eBay sellers -- parts that sound suspiciously like yours (chips that look new and are hard to program and erase consistently or at all)

Yes, guilty :) The lure of $18.99 USD for 5 chips including free shipping on eBay was too good to pass up. I've had two lots of ST27C801 EPROMs from asian suppliers that work just fine, but maybe those are harder to counterfeit as you need a ceramic package and quartz window so not worth it.

Thanks for those links. Finding a major supplier with cheap shipping to NZ for a small order is my usual problem, hence eBay + free shipping.

The good news is I managed to (sort of) test out one key thing last night.

I wrote an auto-detect routine for the 'bios' portion of the system. It scans all the slots and matches the first 16 bytes to a table of 'known' ROMs so all you have to do is insert a new chip and the menu auto-populates. That should be viable in general since the list of SG-1000 / SC-3000 ROMs is reasonably well known. (And you can't scan for an SDSC or SMS tag because they didn't use them on the SG-1000 ROMs).

That actually works pretty well. The only thing I'm struggling with is detecting the difference between an unknown ROM image in a slot and a missing or output disabled chip as I believe the data lines don't have any pull resistors, so don't go to a consistent value when there is nothing driving them (I need to check that again).

Here's how that relates to the Flash chip. Remember earlier I said:

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I've had a look at the pinouts, and the only relevant differences are pins 1 (=A19 on the 27C801 EPROM and =A18 on the AM29F040) and 31 (=A18 on the EPROM and = WE on the Flash part). That section (the 5 highest address lines A15-A19) is all controlled by the 8 bit latch, so a Flash chip should plug straight in fine. I'd just have to rewrite the paging commands in the menu system to keep pin 31 low if you're using a Flash chip instead of an EPROM.

So there are 3 ways to hook a Flash chip onto this multicart.

1. Rewrite the software to always keep pin 31 high (ie. /WE)

2. Hardware jumpers to optionally keep pin 31 high and (maybe) reroute the control signal from pin 31 to pin 1. Then the software addressing works the same way, you just get everything mirrored twice when using the 4MBit EPROM.

3. Keep the software and the hardware the same and rely on the write protection in the Flash chip to stop you damaging the data on the chip. And / Or write an auto-detect routine.

#3 is the interesting one. If you think about the current wiring on the multicart, and you write a paging command for the EPROM layout, then this is how it is interpreted by the EEPROM.

27C801 EPROM A19 A18 A17 A16 A15
29F040 EEPROM A18 /WE A17 A16 A15

That gives you an EEPROM read memory map where slots 0..7 are undefined (because /WE is low and so is /OE), slots 8..15 are defined, slots 16..23 are undefined as /WE and /OE are low, and slots 24..31 are defined.

The auto-scan routine worked on that and gave me a menu consisting of 'unknown' roms in the 0..7 and 16..23 slots, and detected roms in the 8..15 and 24..31 slots.

The AM29F040B datasheet says

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To write a command or command sequence (which includes programming data to the device and erasing sectors of memory), the system must drive WE# and CE# to VIL, and OE# to VIH.

Because /OE is low when I'm reading from the chip I shouldn't be able to overwrite and damage the data on the chip. So that says I can write an autodetect routine that looks for that pattern of unknown ROMs.

Any thoughts on whether that is a reasonable approach in general? Obviously it would be safer to write a flash version of the bios that always keeps pin 31 high and never sets it low (or use hardware jumpers).

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Yes, guilty :) The lure of $18.99 USD for 5 chips including free shipping on eBay was too good to pass up. I've had two lots of ST27C801 EPROMs from asian suppliers that work just fine, but maybe those are harder to counterfeit as you need a ceramic package and quartz window so not worth it.

The other thing I've noticed is that these sellers have good feedback coming from a very high volume of small sales to other Chinese parts dealers. If you look through the feedback and items purchased, it's usually weird stuff like two resistors or one EPROM for just a few dollars along with cut-n-paste comments. This probably builds up good feedback so they can make a scam sale and then repeat the process all over again with a new account.

To be fair I've never had these experiences with eBay parts sellers from other countries, so I'm sure there's still good deals to be had.

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1. Rewrite the software to always keep pin 31 high (ie. /WE)

One concern might be that as the '373 has no reset input, after power-up it could be driving /WE low. Though it is highly unlikely the address and data bus at this time would sequence through the necessary values to issue an erase or program command.

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2. Hardware jumpers to optionally keep pin 31 high and (maybe) reroute the control signal from pin 31 to pin 1. Then the software addressing works the same way, you just get everything mirrored twice when using the 4MBit EPROM.

I think this is a good idea -- when I had suggested using Flash I assumed the PCB layout would be modified for a future production run.

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3. Keep the software and the hardware the same and rely on the write protection in the Flash chip to stop you damaging the data on the chip. And / Or write an auto-detect routine.

Or just have a compile-time constant in the source to enable Flash or EPROM support?

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That gives you an EEPROM read memory map where slots 0..7 are undefined (because /WE is low and so is /OE), slots 8..15 are defined, slots 16..23 are undefined as /WE and /OE are low, and slots 24..31 are defined.

I think you could get away with this. I don't know if the undefined state could be guaranteed across other Flash manufacturers though. I'm pretty sure I've seen parts where OE# could be left grounded and WE# was used to initiate writes or reads (functioning as R/W#).

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Obviously it would be safer to write a flash version of the bios that always keeps pin 31 high and never sets it low (or use hardware jumpers).

I've got to agree, though the other methods seem viable. If this is going into a commercial product I'd stick with the jumpers/PCB change, but for personal use they all seem equally workable.

Thanks for that, much appreciated.

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One concern might be that as the '373 has no reset input, after power-up it could be driving /WE low.

I *think* I have that covered. The 373 latch /OE should be forced high very shortly after power on by the components attached to it. (This is the reset switch plus a feedback loop from '373 latch output pin Q7 back to itself). And the output lines of the 373 all have either pull up or down resistors as appropriate to give them a predictable initial value when /OE is high. So that means that block 31 in the second ROM is always selected on startup (that is where the boot menu / bios goes). The reset switch works by disabling the latch which brings the pull resistors into play which re-selects that boot menu block without having to power off.

Also, from earlier empirical testing (ie. turning computer on / off 50 times or so), it *appears* that the LS373 has internal pull up resistors and will default to all ones at the output if you force /OE low on startup before you latch any values. I couldn't find anything in the datasheets to confirm that though. But in general those output lines should be pretty close to logic 1 very shortly after initial power up.

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If this is going into a commercial product I'd stick with the jumpers/PCB change, but for personal use they all seem equally workable.

At the moment I'm thinking a limited one-off run around Jan-Feb if anyone is interested. I've had a couple of people PM me asking me to make them one already :) But I doubt there will be enough interest to make it worthwhile scaling up to commercial production levels.

So if there are any genuine SC-3000 / SG-1000 enthusiasts who want one of these for their personal use then drop me a line and I'll keep you posted on developments (including whether or not there is enough interest).

That lets me have my fun, share a really cool product with other enthusiasts, and maybe recoup a little bit of the costs I've shelled out for whilst building it :)

If by some miracle lots of people want one, then I'll re-evaluate just how much further to improve the design.

Hi All

Just a progress update for those of you that are following the SC-3000 multicart build.

Well, my Top853 Programmer is dead now. I don't know if it was that last batch of AMD29F040B Flash chips that did it, but now I can't read or write the 27C801 EPROMs either. Ugh. Actually, it could also have been me putting an EPROM in upside down by mistake, although I've got away with that before.

Anyway, I've ordered another Top853 off eBay (hey - it is still the cheapest thing around, and I know it works for the EPROMs). But in the meantime I've made a couple more videos showing some of the features I've been working on, plus a clip of me playing Burglar Bill, a 1980s Mike Boyd classic. That is a cool game, and well worth a look.

You can see the videos plus some extra comments at:

http://sc3000-multicart.com/news.htm#20111111

The other sad news is that is unlikely this design will work on an SG-1000 or Mark III. Charles MacDonald did some detailed work looking at the SG-1000 pinouts (and he kindly reviewed the schematic for the multicart), and it appears that there are some critical differences in which lines are actually connected to the cartridge port. In particular it appears:

That completely stuffs my design on the SG-1000 and Mark III :(

I have a couple of ideas about how I might get around that, but for the moment the Mk II Multicart is for SC-3000 only. Unfortunately I don't have an SG-1000 myself, so I can't confirm, and it probably won't be worthwhile for me to change the design. SC-3000s are easier to find than SG-1000s anyway, and Mark III owners already have other options.

Side note - I found a reasonably priced eBay auction plus shipping for a SG-1000 II, so hopefully I'll be able to see how that is wired up in a couple of weeks.

And I'm still on track to finish most of the cart software tweaks by around Christmas, so feel free to PM me if you're interested in the one-off production run in early 2012.

Cheers

Hi All - another progress report for you.

My replacement Top853 Programmer arrived nice and quick - $45.59 USD including shipping. Thank goodness for eBay, cheap Chinese production, and free shipping! It only took about 10 days to get here from China.

I think the trouble I had with those AMD29F040B Flash chips was just coincidence as they work just fine with the new programmer. They erase, write, and verify perfectly now. In retrospect, the old one was always a bit twitchy. And so far the Flash chips have been running fine in testing on the Multicart. The EPROMs look way cooler though ;)

Anyway, I'm pleased to announce that the Multicart now has 4 new tape games:

Dungeons Beneath Cairo
DBC is an early RPG from Scorpion. You, the mighty THOR have been sent to steal back the ancient Magic Staff which is hidden fifteen dungeons beneath Cairo.

Sorceror's Apprentice
Your seven years of training as a Sorceror's Apprentice have come to a climax. Rescue the Princess Gwen from the dungeons hidden in the depths of the land and prove your ability as a Sorceror.
Another Mike Boyd classic with 80 screens of action adventure

The House
You are Siddy Superspook, Vampire hunter extraordinaire. Search The House, find the Crucifix, and kill Vanessa ze Vampire. A good game from Michael Howard featuring his typical funky title screens and embedded machine code loaders. The program code loads instantly from ROM, but you still get a good 45 second wait as the basic program runs and loads the machine code to high memory. A nice reminder of how times were in the early days :)

Froggy
A very good Frogger clone from Scorpion

In my last post I noted that the current PCB design will not work on an SG-1000 because it doesn't pass all the signals the SC-3000 does out the cart port. I've done more research since then, (and Charles MacDonald was kind enough to let me bounce some ideas off him), so I may run a few breadboard tests on an alternate design that should work on both systems over the next few weeks. We'll see how I go for time :)

And I'm still on track to finish most of the cart software tweaks by around Christmas - New Yearish, so feel free to PM me if you're interested in the one-off production run in early 2012.

Hi All. Here is something I've been wanting to try it for years and it covers an interesting piece of SC-3000 history.

The SC-3000's text mode doesn't let us fit much on the Multicart Boot Menu. So I grabbed Mike Hadrup's awesome Print 64 routines and plugged them under the hood. This lets us have 64 columns of text across the graphics screen instead of the usual 40 in text mode or 32 in graphics mode.

Mike Hadrup was the last editor of Sega Computer Magazine in New Zealand from 1987 to 1988. He was only 18 at the time, but he wrote a lot of really cool toolkit to extend the Basic Interpreter for the SC-3000. One of these utilities was Print 64 (published in Sega Computer Magazine October 1987).

Print 64 works in Screen 2 graphics mode, but it paints two characters into each 8 x 8 pixel block on the screen. The characters are only 3 pixels wide each (with the 4th pixel column being whitespace). So the text is a lot smaller, but it is still looks really good on a CRT. The screenshots don't quite do it justice - you can get a better idea from the video clip.

Print 64 has a simple window system (you specify top left / bottom right of window) and the routines take care of all the text wrapping / scrolling etc. inside that window whilst leaving the rest of the screen intact. Most of the standard layout commands are in there - CR, LF, CLS, simple tabbing system, inverse characters etc.

This made it really easy to extend your own programs. Unfortunately, interest in the SC-3000 was dying out by this stage, and Mike was moving onto bigger and better things at University so we never really saw much software that took advantage of his toolkit. But it is seriously cool and is definitely worth a look. It is also reasonably portable - it doesn't require the IIIB ROM and it wouldn't be too hard to shift it to MSX or SMS legacy mode.

For a bit more detail plus a video clip, check out http://sc3000-multicart.com/news.htm#20111205

Cheers

P64BootMenu_original.png (6.21 KB)

Original Boot Menu - text mode

P64BootMenu_print64.png (5.27 KB)

Print64 version of Boot Menu - 64 columns instead of 40

P64BootMenu_print64Logo.png (6.43 KB)

Print64 Boot Menu with SC-3000 Survivors Logo

It'd be good to get scans of those Sega Computer magazines - our scans stop at March/April 1987.

If you want to out-geek this then you can go to a proportional-width text renderer, which would have the highest readability.

I imagine that the small font would come handy to display long text blurb (back of the box text, etc.) as well.
You've got here the most polished labor-of-love homebrew project going on :)

Quote

It'd be good to get scans of those Sega Computer magazines - our scans stop at March/April 1987.

Sure. I'll try to look at that if I get a bit of time over the Xmas break. I didn't realize they weren't all there.

Quote

If you want to out-geek this then you can go to a proportional-width text renderer, which would have the highest readability.

Cool idea. I read back through some of the earlier SMS Power threads discussing proportional text renderer designs - fascinating reading. I'll stick with Print64 for the first release, but I may take a look at that out of interest when I have a bit more time.

Quote

I imagine that the small font would come handy to display long text blurb (back of the box text, etc.) as well.

Yes, that is another reason for using Print64. I was planning to stick a little blurb in about games I especially liked, or that are interesting for some reason, or for which you need help to figure out the controls etc. (like Sokoban - hold down both joystick buttons for 5 seconds to restart the level).

I think I might struggle to fit the box text in for every game though as I'd like to keep the menu system in a single 32KB block. I can compress the individual text blocks, but various parts of the menu system chew a fair bit of space because I'm using fixed size records for the menu items and jump points and ROM hash table for convenience.

I find writing in assembler is about even parts beauty, elegance, and beating your head into a wall :) So I try to get everything up and running using the simplest technique possible, then improve it gradually.

Quote

You've got here the most polished labor-of-love homebrew project going on :)

I'd just like to say thanks to everyone who has been following the project and has chipped in with some advice or just words of encouragement. I'm getting there :)

Hi All

Just another quick update.

Finalized PCB Layout - extra jumpers

First up, I've pretty well finalized the PCB layout I'm going to use for the production run next year. It will be similar to the original boards, but with two new jumpers. J2 to disable the SRAM on the cart (that was an oversight on my part in original design) and J3 to let you safely insert a Flash EEPROM in the lower ROM slot instead of a 27C801 EPROM if you wish. Given that SMS Power keeps releasing cool new SG-1000 dumps, it is actually quite handy being able to quickly reprogram a chip.

You can see more about that including the patch wires I used to check that the jumper mods will work correctly at:

http://sc3000-multicart.com/news.htm#20111211

The Micro Xevious on Sega SC-3000

I was very excited about the recent Xevious release for the Korean Gamboy and tried it on the multicart. What I got was some really cool graphic malfunctions. The title screen was mangled and your ship was a collection of letters, but otherwise the game functioned pretty well.

So after a fair bit of work in the Meka and BlueMSX debuggers, I found the broken bits. The game is really cool - check out the video in the link below for before and after shots.

1. The code didn't set bit 7 of VDP register 1 in a couple of places. This bit is ignored by the SMS, but on a real TMS99xxA chip it forces 4K VRAM mode. Forcing bit 7 fixes the background tile issues.

2. The code wrote a bad instruction to VDP register $0E in a couple of places. This address is ignored by the SMS, but on a real TMS99xxA it treats it as a write to register 6. This remapped the Sprite Generator table from $3800 back to $0000, which is where the tiles are. That is why your spaceship is made up of letters.

3. You need 8KB of RAM from $E000 to $FFFF. So the 32K multicart works fine. But any other cart you use for this will need onboard RAM.

I have attached the xevious_kr_sc3000.asm patch file.

Check out the full article including a video clip of the before and after at:

http://sc3000-multicart.com/news.htm#20111214

And if you are interested in adding your name to the pre-order list, then go along to

http://sc3000-multicart.com/buy.htm

Cheers

xevious_kr_sc3000.asm (3.77 KB)

Run Xevious on SC-3000 (WLA-DX .asm patch file)

Hi All - Happy New Year!

Just a quick update on the SC-3000 Multicart progress. I'm currently trying to finalize an order for the PCBs with Futurlec, and I've added the Sega Music Editor Demo Cassette to the Multicart.

The Sega Music Editor is a surprisingly capable music composer which gives you a choice of 3 instruments, and allows 3 note chords. You can load / save your compositions to tape and print them out if you have a printer / plotter.

Sega / Grandstand Leisure Ltd released a demo tape that you could buy with 10 demo tunes on it to showcase the cart's capabilities. There is just enough empty space in the Music Editor ROM to embed a compressed copy of the tunes and self extract them when the cart loads.

They are a really nice collection of classical tunes:
Hooked on Computer Classics
The Entertainer
Hark! The Herald Angels Sing
Beethoven's Minuet in G
The Sailor's Hornpipe
From Russia with Love
Yume-No-Tochyu
Rydeen
Nocturne
Beautiful Dreamer

Check out http://sc3000-multicart.com/news.htm#20120108 for more details

I wrote up a short news blurb to hopefully help with the preorders:
http://smspower.org/forums/viewtopic.php?p=69511#69511

Hi All

A couple of updates for you. Firstly, the SC-3000 Multicart PCBs have arrived. Yay! I was expecting them to take a bit longer to arrive, so I still have more tweaking to do on the software. But I'm aiming to ship out the first paid up multicart on 1 March 2012.

You can find more details here:

http://sc3000-multicart.com/news.htm#20120209

By the way - Shrooman - please contact me if you're still interested. I sent a couple of PMs, but haven't heard back and I don't have your email address, sorry.

Secondly, I've added another 13 interesting bits of tape software to the cart.

Arcade Pack I - Gloopa
Arcade Pack II - AFOS (Tron light cycle style game)
Arcade Pack II - Splat (Frogger clone)
Arcade Pack II - Trojans
Arcade Pack III - Blackjack
Colditz (Basic game from Sega Computer Magazine)
Jet Ranger (Basic / Machine code game from Sega Computer Magazine)
Rocket Maths
Color Mixing Basic Demo
Japanese Art Basic Demo
Sega Basic Demo
Scowling Man Basic Demo

The demos are original Sega or Grandstand demos that show off the flexibilty and power of Sega Basic very nicely. And Rocket Maths is a nice little educational game where you have to move the Rocket Ship to the landing dock with the correct answer to a maths problem.

Once again, many thanks to everyone who stumped up with their deposit to make the production run possible. I finally shipped some of the prototypes to friends for testing last week and they were blown away. So I hopefully the end result makes all the waiting worthwhile :)

Cheers

I uploaded a video of me playing Moonbase Alpha on the SC-3000 Multicart. It works like a charm. :)

Hi All

I'm making good progress and it looks like I should hit that 1 March shipping date for the first paid up multicart.

The multicart software is almost finalized now. Here are the most recent changes:

The list of new tape images is at
http://sc3000-multicart.com/news.htm#20120221

And the full list of supported tapes is at
http://sc3000-multicart.com/section3.htm#TapeSoftwareList

Cheers

Hi All

Great news! We've just recently managed to dig up two tape classics that we hadn't seen in 25 years. Many thanks to Glen for spending a couple of days digging through his cupboards.

The Deadly Jewel of Antark is an early RPG by Grant Emms who later wrote Delta Fighter and The Tomb of Nozar.

Satellite Salvage is a fast machine code game by Shayne Burbery. Use your jetpack to pick up the falling pieces of satellite and return them to base whilst dodging the aliens. The aliens get faster and more appear as you go up the levels. Fast and addictive.

Check out the following video for a glimpse of DJOA, Satellite Salvage, plus some of the many tape games from Sega Magazine like Colditz, a Basic graphics demo, the new Text Adventure menu, and a quick look at a funky little Pacman clone called Demon Gobbler.

The lighting isn't the best, and the iPhone struggled with the colors on screen a bit, but you should get the idea :)

Deadly Jewel of Antark and Satellite Salvage just arrived over the past weekend, so I'm going to miss that 1 March shipping date by a couple of days. But nearly there.

Cheers

Hi All

I delivered the first two production SC-3000 Multicarts on March 2. I'll start contacting people with paid up deposits as I work my way through the pre-order list. That could take 3-4 weeks for people near the end, so please be patient. Hopefully quicker than that though :) But feel free to email if you want an update on where you are in the list.

Also I've written a new burn in test routine for the carts so I can leave each one running for an hour or so just looping through reading all the blocks, running checksums, testing the SRAM, and writing any errors to screen.

Cheers

Hi All. Just an update for those of you who pre-ordered the multicart.

The next 8 carts are ready to ship, and I've contacted 5 of you already. The hold up has been the Inkjet Hell I've been through whilst trying to print out a sticky label to go with the cart (thanks to Francesco for letting me borrow the artwork).

Unfortunately, the printer has beaten me. So I'll send anyone who wants one a pdf you can print out and make your own cart label with.

The whole tragic tale is over here http://sc3000-multicart.com/news.htm#20120313

Cheers

Multicart_Label.jpg (30.91 KB)

SC-3000 Multicart Label with template for drilling hole

Hi All

The SC-3000 Multicart User Manual v1.01 is now available for download.

http://sc3000-multicart.com/downloads/SC3000Multicart_User_Manual_v1_01c.pdf

I've tried to summarize and include all the interesting or relevant information that is spread around the website or in the SMS Power Dev Forums into a single document. Most of you will only need the Quickstart Guide and Care of your Multicart sections. But there is also a History section, How it Works, Programming reference, a list of all software shipped with the cart as standard, and the Credits and Acknowledgements section. I may make a few more improvements, but this is getting close to the final version.

I've just about cleared the backlog of orders. There are still a few PCBs left, so get in quick if you want one

http://sc3000-multicart.com/buy.htm

Once again, many thanks to everyone who participated in this project. It has been around 20 months since we conceived the idea, and the last 6 months or so have been crazy busy. But I'm very pleased with how the Multicart has turned out. It does almost everything I had originally envisaged, and in some cases more besides.

Cheers

Hi All

Here is the SC-3000 Multicart Label sheet for you to print your own labels.

http://sc3000-multicart.com/downloads/SC3000Multicart_LabelSheet.pdf

I did my best to make some nice sticky labels to ship with the Multicarts. Unfortunately the label paper I used was very disappointing as it smudges easily, is thin, and has poor color balance.

So my new recommended setup is to print the labels on to glossy photo paper designed for your printer and using original inks. That looks a lot better and it less likely to smudge. (Check out the photo below)

You can then use a glue stick to attach it to your cartridge shell. Cover the label with a tissue or clean piece of paper when you press it into place so you don't get your fingers all over it. And don't use too much glue as it may squidge around the edge of the label when you press it down.

I'm much happier with that. The photo paper is a lot thicker, so it stays flat. And by using a glue stick you may even be able to lift the label later on if you need to unscrew the case.

Cheers

Multicart_Label_vs_PhotoPaper.jpg (122.98 KB)

glossy photo paper vs crappy label paper (sc-3000 multicart)

Author	Message
honestbob Joined: 03 Oct 2011 Posts: 188 Location: New Zealand	SC-3000 / SG-1000 Multicart with Cart and Tape Games Posted: Tue Oct 04, 2011 10:44 am Last edited by honestbob on Tue Mar 27, 2012 10:09 pm; edited 4 times in total
	Hi. We've been working on a couple of interesting projects over at SC-3000 Survivors, and Bock suggested we might like to share our progress with everyone at SMS Power. EDIT: see http://sc3000-multicart.com for progress updates on the Mk II Multicart. If you want to buy one, we are shipping now although there are only a few unreserved PCBs left. You can also find a tutorial on how to build your own 32-n-1 DIP switched based Multicart using only spare change, a shoe-lace and a swiss army knife ;) Note also that this Multicart is for the SC-3000 ONLY. It does not work on the SG-1000, SG-1000 II, or Sega Mark III even though it plays all the known SG-1000 ROMs, and many of the recent Korean / Taiwanese releases that run in legacy mode. I've built a multicart for the SC-3000 / SG-1000 system. It has been through a variety of iterations from breadboards to the current PCB based cart over the past year. It has a joystick / keyboard driven menu system and currently contains around 60-70 games including seventeen SC-3000 tape games that have been converted to load off the Multicart. Check out the video clip. One of my daughters shot the footage on my iPhone. She's only 5, so some of it is a little bit like the Blair Witch project, sorry :) The multicart can run any 32KB, 16KB, or 8KB SC-3000 or SG-1000 ROM, so I won't say much about those. The only ROMs that require minor tweaks are Yie Ar Kung Fu and Konami Ping Pong. Those are MSX ports from the Taiwanese Aaronix console (SG-1000 clone). To get those to work on an SC-3000 you have to explicitly select the Joystick column of the keyboard matrix. So the multicart does that before paging those games into memory. Yie Ar Kung Fu also needs a couple of mods to run with 32KB of RAM. When they ported it from the MSX code they missed a couple of memory locations, so there are 3 or 4 references hard coded to the $e000 range instead of $c000. That works fine with the 2KB of onboard RAM because the SC-3000 mirrors the onboard RAM. But it causes some interesting problems if your cart has 32KB of RAM :) So I patched those locations and it runs fine with 32KB of RAM now. Current tape game list: Moonbase Alpha (graphic adventure plus digitized speech) Burglar Bill (Jet Set Willy style game) Sir Roderick's Quest (graphic adventure) Vortex Blaster (vertical space shooter plus digitized speech) Arcade Pack I - Astro (Asteroids clone) Arcade Pack I - Shootout Arcade Pack III - 1986 (Donkey Kong style game) Arcade Pack III - Bomber Help (Crazy Crypt) Gold Miner (Donkey Kong / QBert crossover set in Haunted Gold Mine) Delta Fighter (large 8-way scrolling game area - shoot the planes, bomb the crap out of the ground installations) Karate Champs (Basic game from Sega Computer Magazine) Castle of Fear (text / graphic adventure) Aerobat (vector graphics Cesenna 152 flight simulator) Caverns of Karanor (Jet Set Willy style graphic adventure) Munchman (Pacman clone) One Day Cricket I just want to say a big thank you to everyone who has supported SMS Power over the years and made it the place it is today. This is the first major post I've made, but I've been a regular reader of the forums over the past couple of years and it is a nice place to hang out :) In particular I'd like to mention the following SMSPower resources which were critical at various times during the build: Charles MacDonald's excellent SC-3000 Hardware notes Maxim's assembler tutorial, aPLib compression library, and commented SF-7000 IPL source were very handy when writing the multicart boot menu. I actually used the SF-7000 IPL as my start point as it already had a text mode display and keyboard matrix parser built in. MikeG for the awesome SMS Reader tutorial. That provided crucial insight early in the process as I was figuring out just how the hell this sparky stuff works Bock - the tireless Ringmaster. Need I say more? Thanks guys :) I still have a fair bit of work to do on the software side. There are another 5-10 tape games I want to convert, and I've been doing things like putting some EPSGMOD files on there, a title screen, a simple audio digitizer / recorder utility (the SC-3000 can record 1-bit audio though the cassette-in port for use in games) etc. But it is getting there. I think I should be done by Christmas. Note - at this stage this is just a prototype hobby cart and I've been building it for fun. Because the PCB design uses EPROMs, it contains copyrighted software when it is shipped. So I'm not sure if we'll ever be able to sell it in its current form, which is a shame because it is a pretty cool piece of kit. You just plug it in and away you go - no configuration required. But I'd welcome any thoughts on that. I'll stick up some technical specs and a bit more info about how it works and why I made certain design choices in a future post. By the way - I have a mostly completed tutorial for how to build your own 32-n-1 DIP switch based SC-3000 / SG-1000 Multicart if anyone is interested. MulticartAssembled_smaller.JPG (515.12 KB) The assembled SC-3000 Survivors Mk II Multicart MulticartPCB_smaller.JPG (133.57 KB) Multicart PCB - Side B (top). Futurlec did a nice job. MulticartPCBs_10PackB_smaller.jpg (105.29 KB) 10 PCBs as shipped by Futurlec - just like a deck of cards. Surprisingly heavy - must be lots of lead in the solder :) IMG_9358_smaller.JPG (107.14 KB) The original 32-n-1 Mk I DIP Switch based Multi-cart (Jan/Feb 2011)

Charles MacDonald Joined: 28 Sep 1999 Posts: 1197	Posted: Tue Oct 04, 2011 9:45 pm
Charles MacDonald Joined: 28 Sep 1999 Posts: 1197	This is really cool! One of the best homebrew things I've seen in a while, and the PCB looks to be of quite high quality. What software did you use to design it that Futurelec accepts? Eagle? About the copyrighted content, I think you could sell the PCB with an EPROM socket and let the user be responsible for supplying a chip and programming it. If you support Flash as well this may help more people as those chips are quite commonplace, cheap (29EE010/29F010, etc.) and a lot of people have device programmers but may not have an EPROM eraser. To make the product immediately usable, you could include a programmed EPROM that has just your menu program and some freeware/homebrew games that would be legal to distribute, and it would be up to the users to then erase and reprogram that part with copyrighted game data (that they've dumped from their own cartridge collection, of course :)

honestbob Joined: 03 Oct 2011 Posts: 188 Location: New Zealand	Posted: Tue Oct 04, 2011 10:38 pm
	Charles MacDonald wrote This is really cool! One of the best homebrew things I've seen in a while, and the PCB looks to be of quite high quality. What software did you use to design it that Futurelec accepts? Eagle? Hi Charles. Thanks for that, much appreciated. I actually used ExpressPCB to design the PCB. Learning to draw a reasonably complex PCB from scratch is a lot of work and most of the PCB drawing programs I looked at were too hard to figure out with my limited knowledge at the time. ExpressPCB is really easy to use, and they have an excellent FAQ on the main things you need to get right when designing a PCB. They also have what looks like a very good automatic online ordering service where you can submit your design direct from the program and it will quote the price for you. And they ship quickly too. So all in all it looks like an excellent service especially if speed is important to you and you're based in the USA. The downside of course is that you are locked into a proprietary format as you really have to place your order through them. I was fine with that originally as they had a reasonable price for their prototype boards (no solder mask layer). But when I went to order I discovered that they only do premium shipping. That is only like $10 in the US, but since I'm in New Zealand it was something like $80 - ie. almost half the price of the order. That annoyed me, so I asked them if they could stick it on slow post but they didn't reply. So I hunted around various forums looking for how to convert ExpressPCB files. There are a few hacks, but it looked like a real pain so I even started to rebuild the design in Eagle. But then I discovered that Futurlec will accept ExpressPCB files. It took about 6 weeks from when I first contacted them. 1 week to place the order and confirm the layout. 3.5 weeks to manufacture, 1.5 weeks to ship. But they were inexpensive, and did all the soldermask and silk-screening which is what makes it look so good. I suspect they did the conversion the same way I'd read about in the forums. I think they used the ExpressPCB program to print out templates to PDFs or similar and then they manually made up masks and drilling files for each part of the process from that. Excellent value for the price, but some poor guy in Thailand is probably being paid $1 a day to do it by hand :) I've had a look at Eagle now and I would probably use that in future to give myself the most flexibility when it came to manufacturing. But for ease of use I still recommend first time home-brewers give ExpressPCB some consideration whilst they are learning the ropes. Charles MacDonald wrote About the copyrighted content, I think you could sell the PCB with an EPROM socket and let the user be responsible for supplying a chip and programming it. If you support Flash as well this may help more people as those chips are quite commonplace, cheap (29EE010/29F010, etc.) and a lot of people have device programmers but may not have an EPROM eraser. Good suggestions, thanks, and I'll look at them in more detail. From memory, Flash memory has different pinouts to the EPROMs on the last few address pins once you go beyond the smaller sizes so I doubt I could do a straight substitution without rewiring. I'll take a look at that though. This design uses the two 8MBit EPROMs which is about the largest size you can easily program with a cheap chinese programmer (approx $50USD on eBay), and which is easily pin compatible with the Z80 address and data lines. That gives you 64 slots of 32KB with my simple paging system. It will work fine with smaller capacity chips, but you halve the amount of games you can store every time you drop down a size (eg. to 4MBit). I'll write a bit more about that soon. Charles MacDonald wrote To make the product immediately usable, you could include a programmed EPROM that has just your menu program and some freeware/homebrew games that would be legal to distribute, and it would be up to the users to then erase and reprogram that part with copyrighted game data (that they've dumped from their own cartridge collection, of course :) :) I'm just not sure how many people would actually bother simply because the SC-3000 was such a niche product so it has correspondingly less die hard fans than something like the Master System. And one of the neatest parts of the design is the copyrighted pre-packaged tape games, which you would lose. But yes, I'll look at that as a possibility, thanks.

honestbob Joined: 03 Oct 2011 Posts: 188 Location: New Zealand	Posted: Wed Oct 05, 2011 9:21 pm
	Charles MacDonald wrote About the copyrighted content, I think you could sell the PCB with an EPROM socket and let the user be responsible for supplying a chip and programming it. If you support Flash as well this may help more people as those chips are quite commonplace, cheap (29EE010/29F010, etc.) and a lot of people have device programmers but may not have an EPROM eraser. Yes, that should work. I've had a look at the pinouts, and the only relevant differences are pins 1 (=A19 on the 27C801 EPROM and =A18 on the AM29F040) and 31 (=A18 on the EPROM and = WE on the Flash part). That section (the 5 highest address lines A15-A19) is all controlled by the 8 bit latch, so a Flash chip should plug straight in fine. I'd just have to rewrite the paging commands in the menu system to keep pin 31 low if you're using a Flash chip instead of an EPROM. So the only downside is that halving of capacity as the largest Flash chip in a DIP 32 package is 4MBit. But with two 4MBit chips you would still get 32 slots of 32KB. Cool idea, thanks. I'll get myself some of those at some stage to play around with.

goldenband Joined: 24 May 2010 Posts: 127 Location: New York	Posted: Wed Oct 05, 2011 10:22 pm
	This is fantastic! I don't know what else to say, really, except that it's the kind of project one hopes someone might do someday -- but it's quite another thing to see it up and running. :) BTW on the copyright issue, there are other highly visible multicarts that come preloaded with games and that, so far, haven't attracted any ugly attention. Since the SC-3000 is a pretty thoroughly abandoned system, it's less likely to get hassled than, say, the ColecoVision. (I think the guy who made a multicart for that system was indeed served with a C&D or something similar -- which is strange, actually: I wonder who owns the copyrights to those games?) Do any of the games have NTSC/PAL compatibility issues? And will the SG-1000 side of things run on a Japanese SG-1000, or a Dina 2-in-1? I'd love to see my Chack'n Pop translation running on real hardware! (Ninja Princess, not so much...)

Charles MacDonald Joined: 28 Sep 1999 Posts: 1197	Posted: Wed Oct 05, 2011 10:38 pm
Charles MacDonald Joined: 28 Sep 1999 Posts: 1197	Quote Yes, that should work. I've had a look at the pinouts, and the only relevant differences are pins 1 (=A19 on the 27C801 EPROM and =A18 on the AM29F040) and 31 (=A18 on the EPROM and = WE on the Flash part). That section (the 5 highest address lines A15-A19) is all controlled by the 8 bit latch, so a Flash chip should plug straight in fine. Ah, I was thinking more along the lines of adding jumpers to the PCB (assuming there's room) to select between an EPROM or Flash pinout so the software could remain unchanged. Quote So the only downside is that halving of capacity as the largest Flash chip in a DIP 32 package is 4MBit. But with two 4MBit chips you would still get 32 slots of 32KB. Oh, I thought you were using aplib to compress the game images before decompressing them to RAM. Any reason why you aren't, like a performance issue? (Maybe it makes game loading too slow?)

honestbob Joined: 03 Oct 2011 Posts: 188 Location: New Zealand	Posted: Wed Oct 05, 2011 10:42 pm
	goldenband wrote This is fantastic! I don't know what else to say, really, except that it's the kind of project one hopes someone might do someday -- but it's quite another thing to see it up and running. :) Thanks. It has been lots of fun but one hell of a learning curve :) Quote BTW on the copyright issue, there are other highly visible multicarts that come preloaded with games and that, so far, haven't attracted any ugly attention. Since the SC-3000 is a pretty thoroughly abandoned system, it's less likely to get hassled than, say, the ColecoVision. True. The Vic20 Megacart is the closest parallel I've seen to what I'd like to do. I see they've offered to give all their profits (if any) to charity which may help. Still - actually going ahead and doing it feels a bit like asking for a lightning bolt to come out of the sky :) Quote Do any of the games have NTSC/PAL compatibility issues? Not really. The SC-3000 / SG-1000 cartridge games were almost all timed to run on an NTSC system. There was no difference in the code distributed to PAL countries, so the only practical difference is that the games run about 10-15% slower on a PAL system because they only have 50 VBLANK interrupts per second instead of 60. Anyone brought up in NZ gets a bit of a shock the first time they try to play the games on an NTSC system and everything runs faster. Quote And will the SG-1000 side of things run on a Japanese SG-1000, or a Dina 2-in-1? I assume so. I only have NZ / PAL SC-3000s here to test on. Once I've tweaked the software a bit more I'll send some of the prototypes out to friends to try on different systems, if they have them. The SC-3000 / SG-1000 games did not have SDSC tags in the header, so I assume this cart will work fine on a Sega Mk III. I'm not familiar with the Dina 2-in-1 (edit - just looked it up http://www.videogameconsolelibrary.com/pg80-dina.htm ). Quote I'd love to see my Chack'n Pop translation running on real hardware! (Ninja Princess, not so much...) Actually, I really liked the Ninja Princess translation :) The Chack ' n ' Pop translation runs fine too - I'm pretty sure I've tried that one out.

honestbob Joined: 03 Oct 2011 Posts: 188 Location: New Zealand	Posted: Wed Oct 05, 2011 11:28 pm
	Quote Oh, I thought you were using aplib to compress the game images before decompressing them to RAM. Any reason why you aren't, like a performance issue? (Maybe it makes game loading too slow?) :) I must finish off that technical overview. Oh well - no time like the present. This is just the direction I came from initially. Take a look at that first DIP switch based multi-cart picture and you'll see what the thinking is. I was learning this stuff as I went and this was a natural way to build it using 1980s style technology. You could have built this multicart PCB design in 1984 (apart from the lack of the 8MBit EPROMs). It just uses 5v TTL logic to select from multiple 32KB blocks within the EPROMs. The design process ran something like this. The SC-3000 has a relatively small number of known ROMs (approx 80-90 games carts). Any one person can probably pick a list of 20-30 favourites they like and forget about the rest as they won't play them more than once. So it was possible to build a single cart that could contain most of the games I ever wanted to play. It later turned out I'm greedy and I wanted more than 30 games on the cart :) The game ROMs are all 32KB or smaller (16KB / 8KB). And the SC-3000 is naturally set up for having the ROM in the lower 32KB of memory, and the RAM in the upper 32KB - either 2KB from C000 to C7FF or 16KB or 32KB with the Basic carts. And there are no known SC-3000 carts that use a paging system - that started with the Master System. So the original paging system was based around just swapping out the lower 32KB of memory space and either using the on-board SRAM, or supplying your own. I always envisaged using an 8-bit latch for this. But the original proof of concept was using a DIP switch. For the Mk I multicart I desoldered a ROM off a Yamato cart. Then I soldered a 32 pin socket onto the original 28 pins. The highest 5 address lines on the 32 pin socket are hard wired to a DIP switch. That manipulates A15 to A19 on the 8MBit EPROM. So depending on the position of the DIP switches, you select a different logical 32KB block within the 8MBit EPROM. The lower 15 address lines A0 to A14 are all hardwired to the A0 to A14 pins on the EPROMs. You then turn on the computer, and it is just as if a different cart had been plugged in. There are some obvious extensions to this, including using a 6th pin on the DIP switch wired to A14 through an OR gate so that either the Z80 A14 line OR the DIP switch can set A14 high. That gives you 16KB paging blocks. I've tried that and it works fine. That is actually handy because there are ummm... something like twenty two 16KB or 8KB ROMs, so you can pack more in. Unfortunately I ran out of room on the PCB (and time and patience, it has to be said), to do 16KB pages on the first PCB prototype. However I have left one bit of the 8-bit latch free to try this as a future mod. I built and tested all this stuff on breadboards and I had to learn as I proceeded since my starting knowledge was reasonably close to zero :) The PCB version uses a 74LS373 8-bit latch in place of the DIP switch. This is connected to the SC-3000 I/O bus on port $e0. The $e0 to $ff range is used by the SF-7000, so I knew this range would be clear of interference. After reading your hardware notes I knew there could be unpredictable behaviour if I put it lower even if it wasn't on one of the 'known' SC-3000 ports. The PCB also has 32KB of SRAM. This is mapped at $8000 to $FFFF, just like the Basic IIIB cart. So it is also perfectly suited to running tape games. Those always run in the upper 32KB of RAM and expect to have the IIIB ROM in the lower 32KB. I just need to write a custom loader for each one to load from the multi-cart paging system instead of calling the tape load routines. Single-load tape games are easy. You just copy the data to $9800, reset the basic pointers at $8160, and jump into the basic RUN entry point. Multi-load games with seperate title screens etc. are harder and need the custom load treatment. But apart from loading from the multi-cart, the games load in the same sequence they did when loaded from tape, which is kind of neat. So the ROMs are all uncompressed which makes for a nice simple hardware design with a very basic paging system. Where I have been using compression is in the loading of tape games. Those are copied into the top 32KB of RAM, so some of those are compressed to save space. Plus I've been playing around with digitized photos and music files etc. so the aPLib compressor is very handy for that. The main components of interest on the PCB are: 2 x 27C801 8MBit EPROMs 32KB SRAM 74LS373 8-bit latch Reset switch to restore the boot menu without having to switch power off Jumper between B02 and B03 pins to allow you to disable 32KB SRAM and use the SC-3000's onboard 2KB SRAM instead Various TTL glue logic chips The 74LS373 8 bit latch does 3 things: It controls the A15 to A19 pins on the EPROMs to select another logical block It selects which of the two ROMs is active. The PCB will work happily with a single ROM It enables / disables itself. This is a feedback loop for the Reset switch on the PCB which is there to get the boot menu back without powering off The Reset switch behaviour is interesting. Unfortunately the SC-3000 does not pass the Z80 reset line out to the cartridge port. So the hard reset switch on the multicart disables the 8 bit latch which selects the last slot on the second ROM because the 74LS373 has internal pull up resistors. This is where the boot menu goes. You then press the Reset button on the SC-3000 keyboard which triggers the Reset handler in the boot menu block which basically returns back to $0000, cleans up the system, and displays the boot menu. I have subsequently learned about other ways I could have built the cart. But I actually really like the 'old skool' design, and the TTL components are like old friends :) Off in the distant future I have some vague plans for something using a more modern design, but hopefully the above explains where I've come from and how we ended up here. CompletedCart_InCase01.JPG (64.89 KB) 32-n-1 Mk I Multicart - I removed the ROM from a Yamato cart, and added a 32 pin socket and DIP switch

Shroo-man Joined: 26 Mar 2007 Posts: 16 Location: Australia	Posted: Tue Oct 11, 2011 2:29 am
	you're a genius that is absolutely amazing stuff! I must congratulate you on such an awesome job. and was great to finally got to see Delta Fighter and Caverns of Karanor in action - brilliant! the quality is levels above most of the more common locally produced AU/NZ software and a refreshing change from the mass of arcade games released on cartridge. I'd definitely be interested in your tutorial of how to make one, also where do you buy the multicart PCB from? sent pm

honestbob Joined: 03 Oct 2011 Posts: 188 Location: New Zealand	SC-3000 Multicart website and 32-n-1 tutorial Posted: Thu Oct 20, 2011 11:55 am
	Shroo-man wrote I'd definitely be interested in your tutorial of how to make one Hi All. I've finally tidied up most of my draft SC-3000 multicart notes into a website: http://sc3000-multicart.com Check out the tutorial at http://sc3000-multicart.com/section1.htm that shows you how to build your own 32-n-1 SC-3000 / SG-1000 multicart by adding a DIP switch to an existing cart. The tutorial is quite detailed and was inspired by the excellent SMS Reader tutorial. The DIP switch based cart isn't as nice as the Mk II boot menu version, but it is still pretty cool and it is reasonably easy to make yourself. So have a go, and let me know how you get on :)

honestbob Joined: 03 Oct 2011 Posts: 188 Location: New Zealand	AM29F040B EEPROMs and Top853 Programmer Posted: Thu Oct 27, 2011 5:30 pm
	Hi All Has anyone run into this before? I'm trying out Charles' suggestion of using Flash / EEPROMs in the multicart. I bought some AM29F040B (4MBit Flash) DIP32 chips off eBay, but I'm having trouble programming them. The chips are showing as all FF when first used, but the first write tends to have intermittent errors, and the Erase / Blank operations on my EPROM programmer just return errors so I can't easily wipe and overwrite them. My EPROM programmer is a Top853 and is one of the cheapest you can buy on eBay. It has AM29F040 in its supported list, but not AM29F040B. Later revisions of this programmer (like the Top2004 and later) have the AM29F040B explicitly listed as well as the AM29F040. And being a cheap chinglish programmer documentation is almost non-existent. Looking at the datasheets for both chips, there doesn't seem to be too much difference, so I'd have hoped they were write compatible. The AM29F040B datasheet says: Quote This device is manufactured using AMD’s 0.32 μm process technology, and offers all the features and benefits of the Am29F040, which was manufactured using 0.5 μm process technology. In addtion, the Am29F040B has a second toggle bit, DQ2, and also offers the ability to program in the Erase Suspend mode. Any thoughts anyone? I don't really want to buy another programmer as it works just fine on the ST27C801 EPROMs I've been using up to this point. Or could the chips be faulty? I've tried two out of the 5 so far. They have a 1998 date stamp, and are supposed to be new. The pins were still in their 'wide' configuration, so it doesn't look like they've been socketed before. Ta.

Charles MacDonald Joined: 28 Sep 1999 Posts: 1197	Posted: Thu Oct 27, 2011 6:41 pm
Charles MacDonald Joined: 28 Sep 1999 Posts: 1197	Quote My EPROM programmer is a Top853 and is one of the cheapest you can buy on eBay. I have the Top853 too and it works with the AM29F040, though I can't recall if I used a "B" part specifically. I have used AM29F040 and AM29F040B's interchangeably in the past with a different programmer that only supported the AM29F040, and it could erase, program, and verify the "B" parts just fine. So I agree that that are no major differences between the two. Quote Or could the chips be faulty? I've tried two out of the 5 so far. They have a 1998 date stamp, and are supposed to be new. The pins were still in their 'wide' configuration, so it doesn't look like they've been socketed before. Did you get these from eBay by any chance? I've had a lot of problems in recent time with bad chips from Chinese eBay sellers -- parts that sound suspiciously like yours (chips that look new and are hard to program and erase consistently or at all) I'd stick to official distributors if you can manage -- anyone listed at findchips.com or octopart.com is usually a safe bet. These days the 29F040 is harder to get and most DIP flash is 29F010 and 29EE010 which is only 128K.

honestbob Joined: 03 Oct 2011 Posts: 188 Location: New Zealand	Posted: Thu Oct 27, 2011 8:38 pm
	Quote Did you get these from eBay by any chance? I've had a lot of problems in recent time with bad chips from Chinese eBay sellers -- parts that sound suspiciously like yours (chips that look new and are hard to program and erase consistently or at all) Yes, guilty :) The lure of $18.99 USD for 5 chips including free shipping on eBay was too good to pass up. I've had two lots of ST27C801 EPROMs from asian suppliers that work just fine, but maybe those are harder to counterfeit as you need a ceramic package and quartz window so not worth it. Thanks for those links. Finding a major supplier with cheap shipping to NZ for a small order is my usual problem, hence eBay + free shipping. The good news is I managed to (sort of) test out one key thing last night. I wrote an auto-detect routine for the 'bios' portion of the system. It scans all the slots and matches the first 16 bytes to a table of 'known' ROMs so all you have to do is insert a new chip and the menu auto-populates. That should be viable in general since the list of SG-1000 / SC-3000 ROMs is reasonably well known. (And you can't scan for an SDSC or SMS tag because they didn't use them on the SG-1000 ROMs). That actually works pretty well. The only thing I'm struggling with is detecting the difference between an unknown ROM image in a slot and a missing or output disabled chip as I believe the data lines don't have any pull resistors, so don't go to a consistent value when there is nothing driving them (I need to check that again). Here's how that relates to the Flash chip. Remember earlier I said: Quote I've had a look at the pinouts, and the only relevant differences are pins 1 (=A19 on the 27C801 EPROM and =A18 on the AM29F040) and 31 (=A18 on the EPROM and = WE on the Flash part). That section (the 5 highest address lines A15-A19) is all controlled by the 8 bit latch, so a Flash chip should plug straight in fine. I'd just have to rewrite the paging commands in the menu system to keep pin 31 low if you're using a Flash chip instead of an EPROM. So there are 3 ways to hook a Flash chip onto this multicart. 1. Rewrite the software to always keep pin 31 high (ie. /WE) 2. Hardware jumpers to optionally keep pin 31 high and (maybe) reroute the control signal from pin 31 to pin 1. Then the software addressing works the same way, you just get everything mirrored twice when using the 4MBit EPROM. 3. Keep the software and the hardware the same and rely on the write protection in the Flash chip to stop you damaging the data on the chip. And / Or write an auto-detect routine. #3 is the interesting one. If you think about the current wiring on the multicart, and you write a paging command for the EPROM layout, then this is how it is interpreted by the EEPROM. 27C801 EPROM A19 A18 A17 A16 A15 29F040 EEPROM A18 /WE A17 A16 A15 That gives you an EEPROM read memory map where slots 0..7 are undefined (because /WE is low and so is /OE), slots 8..15 are defined, slots 16..23 are undefined as /WE and /OE are low, and slots 24..31 are defined. The auto-scan routine worked on that and gave me a menu consisting of 'unknown' roms in the 0..7 and 16..23 slots, and detected roms in the 8..15 and 24..31 slots. The AM29F040B datasheet says Quote To write a command or command sequence (which includes programming data to the device and erasing sectors of memory), the system must drive WE# and CE# to VIL, and OE# to VIH. Because /OE is low when I'm reading from the chip I shouldn't be able to overwrite and damage the data on the chip. So that says I can write an autodetect routine that looks for that pattern of unknown ROMs. Any thoughts on whether that is a reasonable approach in general? Obviously it would be safer to write a flash version of the bios that always keeps pin 31 high and never sets it low (or use hardware jumpers).

Charles MacDonald Joined: 28 Sep 1999 Posts: 1197	Posted: Thu Oct 27, 2011 9:43 pm
Charles MacDonald Joined: 28 Sep 1999 Posts: 1197	Quote Yes, guilty :) The lure of $18.99 USD for 5 chips including free shipping on eBay was too good to pass up. I've had two lots of ST27C801 EPROMs from asian suppliers that work just fine, but maybe those are harder to counterfeit as you need a ceramic package and quartz window so not worth it. The other thing I've noticed is that these sellers have good feedback coming from a very high volume of small sales to other Chinese parts dealers. If you look through the feedback and items purchased, it's usually weird stuff like two resistors or one EPROM for just a few dollars along with cut-n-paste comments. This probably builds up good feedback so they can make a scam sale and then repeat the process all over again with a new account. To be fair I've never had these experiences with eBay parts sellers from other countries, so I'm sure there's still good deals to be had. Quote 1. Rewrite the software to always keep pin 31 high (ie. /WE) One concern might be that as the '373 has no reset input, after power-up it could be driving /WE low. Though it is highly unlikely the address and data bus at this time would sequence through the necessary values to issue an erase or program command. Quote 2. Hardware jumpers to optionally keep pin 31 high and (maybe) reroute the control signal from pin 31 to pin 1. Then the software addressing works the same way, you just get everything mirrored twice when using the 4MBit EPROM. I think this is a good idea -- when I had suggested using Flash I assumed the PCB layout would be modified for a future production run. Quote 3. Keep the software and the hardware the same and rely on the write protection in the Flash chip to stop you damaging the data on the chip. And / Or write an auto-detect routine. Or just have a compile-time constant in the source to enable Flash or EPROM support? Quote That gives you an EEPROM read memory map where slots 0..7 are undefined (because /WE is low and so is /OE), slots 8..15 are defined, slots 16..23 are undefined as /WE and /OE are low, and slots 24..31 are defined. I think you could get away with this. I don't know if the undefined state could be guaranteed across other Flash manufacturers though. I'm pretty sure I've seen parts where OE# could be left grounded and WE# was used to initiate writes or reads (functioning as R/W#). Quote Obviously it would be safer to write a flash version of the bios that always keeps pin 31 high and never sets it low (or use hardware jumpers). I've got to agree, though the other methods seem viable. If this is going into a commercial product I'd stick with the jumpers/PCB change, but for personal use they all seem equally workable.

honestbob Joined: 03 Oct 2011 Posts: 188 Location: New Zealand	Posted: Thu Oct 27, 2011 10:22 pm
	Thanks for that, much appreciated. Quote One concern might be that as the '373 has no reset input, after power-up it could be driving /WE low. I think I have that covered. The 373 latch /OE should be forced high very shortly after power on by the components attached to it. (This is the reset switch plus a feedback loop from '373 latch output pin Q7 back to itself). And the output lines of the 373 all have either pull up or down resistors as appropriate to give them a predictable initial value when /OE is high. So that means that block 31 in the second ROM is always selected on startup (that is where the boot menu / bios goes). The reset switch works by disabling the latch which brings the pull resistors into play which re-selects that boot menu block without having to power off. Also, from earlier empirical testing (ie. turning computer on / off 50 times or so), it appears that the LS373 has internal pull up resistors and will default to all ones at the output if you force /OE low on startup before you latch any values. I couldn't find anything in the datasheets to confirm that though. But in general those output lines should be pretty close to logic 1 very shortly after initial power up. Quote If this is going into a commercial product I'd stick with the jumpers/PCB change, but for personal use they all seem equally workable. At the moment I'm thinking a limited one-off run around Jan-Feb if anyone is interested. I've had a couple of people PM me asking me to make them one already :) But I doubt there will be enough interest to make it worthwhile scaling up to commercial production levels. So if there are any genuine SC-3000 / SG-1000 enthusiasts who want one of these for their personal use then drop me a line and I'll keep you posted on developments (including whether or not there is enough interest). That lets me have my fun, share a really cool product with other enthusiasts, and maybe recoup a little bit of the costs I've shelled out for whilst building it :) If by some miracle lots of people want one, then I'll re-evaluate just how much further to improve the design.

honestbob Joined: 03 Oct 2011 Posts: 188 Location: New Zealand	Multicart Nov 2011 Update Posted: Thu Nov 10, 2011 10:16 pm
	Hi All Just a progress update for those of you that are following the SC-3000 multicart build. Well, my Top853 Programmer is dead now. I don't know if it was that last batch of AMD29F040B Flash chips that did it, but now I can't read or write the 27C801 EPROMs either. Ugh. Actually, it could also have been me putting an EPROM in upside down by mistake, although I've got away with that before. Anyway, I've ordered another Top853 off eBay (hey - it is still the cheapest thing around, and I know it works for the EPROMs). But in the meantime I've made a couple more videos showing some of the features I've been working on, plus a clip of me playing Burglar Bill, a 1980s Mike Boyd classic. That is a cool game, and well worth a look. You can see the videos plus some extra comments at: http://sc3000-multicart.com/news.htm#20111111 The other sad news is that is unlikely this design will work on an SG-1000 or Mark III. Charles MacDonald did some detailed work looking at the SG-1000 pinouts (and he kindly reviewed the schematic for the multicart), and it appears that there are some critical differences in which lines are actually connected to the cartridge port. In particular it appears: the Z80 /IORQ signal is not passed out The Mark 3 and SG-1000 don't have IOR, IOW, and RD, WR aren't gated with MREQ so they are asserted for both I/O and MREQ accesses That completely stuffs my design on the SG-1000 and Mark III :( I have a couple of ideas about how I might get around that, but for the moment the Mk II Multicart is for SC-3000 only. Unfortunately I don't have an SG-1000 myself, so I can't confirm, and it probably won't be worthwhile for me to change the design. SC-3000s are easier to find than SG-1000s anyway, and Mark III owners already have other options. Side note - I found a reasonably priced eBay auction plus shipping for a SG-1000 II, so hopefully I'll be able to see how that is wired up in a couple of weeks. And I'm still on track to finish most of the cart software tweaks by around Christmas, so feel free to PM me if you're interested in the one-off production run in early 2012. Cheers

honestbob Joined: 03 Oct 2011 Posts: 188 Location: New Zealand	4 more tape games added to SC-3000 multicart Posted: Sat Nov 19, 2011 9:44 am
	Hi All - another progress report for you. My replacement Top853 Programmer arrived nice and quick - $45.59 USD including shipping. Thank goodness for eBay, cheap Chinese production, and free shipping! It only took about 10 days to get here from China. I think the trouble I had with those AMD29F040B Flash chips was just coincidence as they work just fine with the new programmer. They erase, write, and verify perfectly now. In retrospect, the old one was always a bit twitchy. And so far the Flash chips have been running fine in testing on the Multicart. The EPROMs look way cooler though ;) Anyway, I'm pleased to announce that the Multicart now has 4 new tape games: Dungeons Beneath Cairo DBC is an early RPG from Scorpion. You, the mighty THOR have been sent to steal back the ancient Magic Staff which is hidden fifteen dungeons beneath Cairo. Sorceror's Apprentice Your seven years of training as a Sorceror's Apprentice have come to a climax. Rescue the Princess Gwen from the dungeons hidden in the depths of the land and prove your ability as a Sorceror. Another Mike Boyd classic with 80 screens of action adventure The House You are Siddy Superspook, Vampire hunter extraordinaire. Search The House, find the Crucifix, and kill Vanessa ze Vampire. A good game from Michael Howard featuring his typical funky title screens and embedded machine code loaders. The program code loads instantly from ROM, but you still get a good 45 second wait as the basic program runs and loads the machine code to high memory. A nice reminder of how times were in the early days :) Froggy A very good Frogger clone from Scorpion In my last post I noted that the current PCB design will not work on an SG-1000 because it doesn't pass all the signals the SC-3000 does out the cart port. I've done more research since then, (and Charles MacDonald was kind enough to let me bounce some ideas off him), so I may run a few breadboard tests on an alternate design that should work on both systems over the next few weeks. We'll see how I go for time :) And I'm still on track to finish most of the cart software tweaks by around Christmas - New Yearish, so feel free to PM me if you're interested in the one-off production run in early 2012.

honestbob Joined: 03 Oct 2011 Posts: 188 Location: New Zealand	64 Column Printing on the SC-3000 - Mike Hadrup's Print 64 Posted: Mon Dec 05, 2011 10:30 am
	Hi All. Here is something I've been wanting to try it for years and it covers an interesting piece of SC-3000 history. The SC-3000's text mode doesn't let us fit much on the Multicart Boot Menu. So I grabbed Mike Hadrup's awesome Print 64 routines and plugged them under the hood. This lets us have 64 columns of text across the graphics screen instead of the usual 40 in text mode or 32 in graphics mode. Mike Hadrup was the last editor of Sega Computer Magazine in New Zealand from 1987 to 1988. He was only 18 at the time, but he wrote a lot of really cool toolkit to extend the Basic Interpreter for the SC-3000. One of these utilities was Print 64 (published in Sega Computer Magazine October 1987). Print 64 works in Screen 2 graphics mode, but it paints two characters into each 8 x 8 pixel block on the screen. The characters are only 3 pixels wide each (with the 4th pixel column being whitespace). So the text is a lot smaller, but it is still looks really good on a CRT. The screenshots don't quite do it justice - you can get a better idea from the video clip. Print 64 has a simple window system (you specify top left / bottom right of window) and the routines take care of all the text wrapping / scrolling etc. inside that window whilst leaving the rest of the screen intact. Most of the standard layout commands are in there - CR, LF, CLS, simple tabbing system, inverse characters etc. This made it really easy to extend your own programs. Unfortunately, interest in the SC-3000 was dying out by this stage, and Mike was moving onto bigger and better things at University so we never really saw much software that took advantage of his toolkit. But it is seriously cool and is definitely worth a look. It is also reasonably portable - it doesn't require the IIIB ROM and it wouldn't be too hard to shift it to MSX or SMS legacy mode. For a bit more detail plus a video clip, check out http://sc3000-multicart.com/news.htm#20111205 Cheers P64BootMenu_original.png (6.21 KB) Original Boot Menu - text mode P64BootMenu_print64.png (5.27 KB) Print64 version of Boot Menu - 64 columns instead of 40 P64BootMenu_print64Logo.png (6.43 KB) Print64 Boot Menu with SC-3000 Survivors Logo

Maxim Site Admin Joined: 19 Oct 1999 Posts: 14740 Location: London	Posted: Mon Dec 05, 2011 12:00 pm
	It'd be good to get scans of those Sega Computer magazines - our scans stop at March/April 1987. If you want to out-geek this then you can go to a proportional-width text renderer, which would have the highest readability.

Bock Site Admin Joined: 08 Jul 2001 Posts: 8649 Location: Paris, France	Posted: Mon Dec 05, 2011 2:00 pm
	I imagine that the small font would come handy to display long text blurb (back of the box text, etc.) as well. You've got here the most polished labor-of-love homebrew project going on :)

honestbob Joined: 03 Oct 2011 Posts: 188 Location: New Zealand	Posted: Sun Dec 11, 2011 9:43 am
	Quote It'd be good to get scans of those Sega Computer magazines - our scans stop at March/April 1987. Sure. I'll try to look at that if I get a bit of time over the Xmas break. I didn't realize they weren't all there. Quote If you want to out-geek this then you can go to a proportional-width text renderer, which would have the highest readability. Cool idea. I read back through some of the earlier SMS Power threads discussing proportional text renderer designs - fascinating reading. I'll stick with Print64 for the first release, but I may take a look at that out of interest when I have a bit more time. Quote I imagine that the small font would come handy to display long text blurb (back of the box text, etc.) as well. Yes, that is another reason for using Print64. I was planning to stick a little blurb in about games I especially liked, or that are interesting for some reason, or for which you need help to figure out the controls etc. (like Sokoban - hold down both joystick buttons for 5 seconds to restart the level). I think I might struggle to fit the box text in for every game though as I'd like to keep the menu system in a single 32KB block. I can compress the individual text blocks, but various parts of the menu system chew a fair bit of space because I'm using fixed size records for the menu items and jump points and ROM hash table for convenience. I find writing in assembler is about even parts beauty, elegance, and beating your head into a wall :) So I try to get everything up and running using the simplest technique possible, then improve it gradually. Quote You've got here the most polished labor-of-love homebrew project going on :) I'd just like to say thanks to everyone who has been following the project and has chipped in with some advice or just words of encouragement. I'm getting there :)

honestbob Joined: 03 Oct 2011 Posts: 188 Location: New Zealand	Xevious on Multicart and PCB Hacks Posted: Tue Dec 13, 2011 10:14 pm
	Hi All Just another quick update. Finalized PCB Layout - extra jumpers First up, I've pretty well finalized the PCB layout I'm going to use for the production run next year. It will be similar to the original boards, but with two new jumpers. J2 to disable the SRAM on the cart (that was an oversight on my part in original design) and J3 to let you safely insert a Flash EEPROM in the lower ROM slot instead of a 27C801 EPROM if you wish. Given that SMS Power keeps releasing cool new SG-1000 dumps, it is actually quite handy being able to quickly reprogram a chip. You can see more about that including the patch wires I used to check that the jumper mods will work correctly at: http://sc3000-multicart.com/news.htm#20111211 The Micro Xevious on Sega SC-3000 I was very excited about the recent Xevious release for the Korean Gamboy and tried it on the multicart. What I got was some really cool graphic malfunctions. The title screen was mangled and your ship was a collection of letters, but otherwise the game functioned pretty well. So after a fair bit of work in the Meka and BlueMSX debuggers, I found the broken bits. The game is really cool - check out the video in the link below for before and after shots. 1. The code didn't set bit 7 of VDP register 1 in a couple of places. This bit is ignored by the SMS, but on a real TMS99xxA chip it forces 4K VRAM mode. Forcing bit 7 fixes the background tile issues. 2. The code wrote a bad instruction to VDP register $0E in a couple of places. This address is ignored by the SMS, but on a real TMS99xxA it treats it as a write to register 6. This remapped the Sprite Generator table from $3800 back to $0000, which is where the tiles are. That is why your spaceship is made up of letters. 3. You need 8KB of RAM from $E000 to $FFFF. So the 32K multicart works fine. But any other cart you use for this will need onboard RAM. I have attached the xevious_kr_sc3000.asm patch file. Check out the full article including a video clip of the before and after at: http://sc3000-multicart.com/news.htm#20111214 And if you are interested in adding your name to the pre-order list, then go along to http://sc3000-multicart.com/buy.htm Cheers xevious_kr_sc3000.asm (3.77 KB) Run Xevious on SC-3000 (WLA-DX .asm patch file)

honestbob Joined: 03 Oct 2011 Posts: 188 Location: New Zealand	Sega Music Editor Demo Cassette on Multicart Posted: Sun Jan 08, 2012 10:04 am
	Hi All - Happy New Year! Just a quick update on the SC-3000 Multicart progress. I'm currently trying to finalize an order for the PCBs with Futurlec, and I've added the Sega Music Editor Demo Cassette to the Multicart. The Sega Music Editor is a surprisingly capable music composer which gives you a choice of 3 instruments, and allows 3 note chords. You can load / save your compositions to tape and print them out if you have a printer / plotter. Sega / Grandstand Leisure Ltd released a demo tape that you could buy with 10 demo tunes on it to showcase the cart's capabilities. There is just enough empty space in the Music Editor ROM to embed a compressed copy of the tunes and self extract them when the cart loads. They are a really nice collection of classical tunes: Hooked on Computer Classics The Entertainer Hark! The Herald Angels Sing Beethoven's Minuet in G The Sailor's Hornpipe From Russia with Love Yume-No-Tochyu Rydeen Nocturne Beautiful Dreamer Check out http://sc3000-multicart.com/news.htm#20120108 for more details

Bock Site Admin Joined: 08 Jul 2001 Posts: 8649 Location: Paris, France	Posted: Sun Jan 08, 2012 12:44 pm
	I wrote up a short news blurb to hopefully help with the preorders: http://smspower.org/forums/viewtopic.php?p=69511#69511

honestbob Joined: 03 Oct 2011 Posts: 188 Location: New Zealand	SC-3000 Multicart PCBs are here - 1 March 2012 shipping Posted: Wed Feb 08, 2012 9:39 pm
	Hi All A couple of updates for you. Firstly, the SC-3000 Multicart PCBs have arrived. Yay! I was expecting them to take a bit longer to arrive, so I still have more tweaking to do on the software. But I'm aiming to ship out the first paid up multicart on 1 March 2012. You can find more details here: http://sc3000-multicart.com/news.htm#20120209 By the way - Shrooman - please contact me if you're still interested. I sent a couple of PMs, but haven't heard back and I don't have your email address, sorry. Secondly, I've added another 13 interesting bits of tape software to the cart. Arcade Pack I - Gloopa Arcade Pack II - AFOS (Tron light cycle style game) Arcade Pack II - Splat (Frogger clone) Arcade Pack II - Trojans Arcade Pack III - Blackjack Colditz (Basic game from Sega Computer Magazine) Jet Ranger (Basic / Machine code game from Sega Computer Magazine) Rocket Maths Color Mixing Basic Demo Japanese Art Basic Demo Sega Basic Demo Scowling Man Basic Demo The demos are original Sega or Grandstand demos that show off the flexibilty and power of Sega Basic very nicely. And Rocket Maths is a nice little educational game where you have to move the Rocket Ship to the landing dock with the correct answer to a maths problem. Once again, many thanks to everyone who stumped up with their deposit to make the production run possible. I finally shipped some of the prototypes to friends for testing last week and they were blown away. So I hopefully the end result makes all the waiting worthwhile :) Cheers

Bock Site Admin Joined: 08 Jul 2001 Posts: 8649 Location: Paris, France	Posted: Fri Feb 10, 2012 1:05 am
	I uploaded a video of me playing Moonbase Alpha on the SC-3000 Multicart. It works like a charm. :)

honestbob Joined: 03 Oct 2011 Posts: 188 Location: New Zealand	Added 40 more tape images to SC-3000 Multicart Posted: Wed Feb 22, 2012 9:20 pm
	Hi All I'm making good progress and it looks like I should hit that 1 March shipping date for the first paid up multicart. The multicart software is almost finalized now. Here are the most recent changes: Added another 40 or so tape images including 18 from Sega Computer Magazine (see below). That gives us a grand total of over 70 tape images. Compressed existing tape games Added Text Adventure Menu Updated Autodetect list for several Korean / Taiwanese ROMs, and the Japanese Educational carts Fixed the auto-start bug on the Arcade Pack games Print 64 Menu scrolls as quickly as Text Mode menu Optional Infinite Lives cheat mode for Caverns of Karanor The list of new tape images is at http://sc3000-multicart.com/news.htm#20120221 And the full list of supported tapes is at http://sc3000-multicart.com/section3.htm#TapeSoftwareList Cheers

honestbob Joined: 03 Oct 2011 Posts: 188 Location: New Zealand	Deadly Jewel of Antark and Satellite Salvage video Posted: Mon Feb 27, 2012 5:29 pm
	Hi All Great news! We've just recently managed to dig up two tape classics that we hadn't seen in 25 years. Many thanks to Glen for spending a couple of days digging through his cupboards. The Deadly Jewel of Antark is an early RPG by Grant Emms who later wrote Delta Fighter and The Tomb of Nozar. Satellite Salvage is a fast machine code game by Shayne Burbery. Use your jetpack to pick up the falling pieces of satellite and return them to base whilst dodging the aliens. The aliens get faster and more appear as you go up the levels. Fast and addictive. Check out the following video for a glimpse of DJOA, Satellite Salvage, plus some of the many tape games from Sega Magazine like Colditz, a Basic graphics demo, the new Text Adventure menu, and a quick look at a funky little Pacman clone called Demon Gobbler. The lighting isn't the best, and the iPhone struggled with the colors on screen a bit, but you should get the idea :) Deadly Jewel of Antark and Satellite Salvage just arrived over the past weekend, so I'm going to miss that 1 March shipping date by a couple of days. But nearly there. Cheers

honestbob Joined: 03 Oct 2011 Posts: 188 Location: New Zealand	Shipped first two production multicarts Posted: Sun Mar 04, 2012 9:50 am
	Hi All I delivered the first two production SC-3000 Multicarts on March 2. I'll start contacting people with paid up deposits as I work my way through the pre-order list. That could take 3-4 weeks for people near the end, so please be patient. Hopefully quicker than that though :) But feel free to email if you want an update on where you are in the list. Also I've written a new burn in test routine for the carts so I can leave each one running for an hour or so just looping through reading all the blocks, running checksums, testing the SRAM, and writing any errors to screen. Cheers

honestbob Joined: 03 Oct 2011 Posts: 188 Location: New Zealand	Next 8 carts ready to ship Posted: Mon Mar 12, 2012 10:20 pm
	Hi All. Just an update for those of you who pre-ordered the multicart. The next 8 carts are ready to ship, and I've contacted 5 of you already. The hold up has been the Inkjet Hell I've been through whilst trying to print out a sticky label to go with the cart (thanks to Francesco for letting me borrow the artwork). Unfortunately, the printer has beaten me. So I'll send anyone who wants one a pdf you can print out and make your own cart label with. The whole tragic tale is over here http://sc3000-multicart.com/news.htm#20120313 Cheers Multicart_Label.jpg (30.91 KB) SC-3000 Multicart Label with template for drilling hole

honestbob Joined: 03 Oct 2011 Posts: 188 Location: New Zealand	Multicart User Manual Posted: Thu Mar 22, 2012 2:54 am
	Hi All The SC-3000 Multicart User Manual v1.01 is now available for download. http://sc3000-multicart.com/downloads/SC3000Multicart_User_Manual_v1_01c.pdf I've tried to summarize and include all the interesting or relevant information that is spread around the website or in the SMS Power Dev Forums into a single document. Most of you will only need the Quickstart Guide and Care of your Multicart sections. But there is also a History section, How it Works, Programming reference, a list of all software shipped with the cart as standard, and the Credits and Acknowledgements section. I may make a few more improvements, but this is getting close to the final version. I've just about cleared the backlog of orders. There are still a few PCBs left, so get in quick if you want one http://sc3000-multicart.com/buy.htm Once again, many thanks to everyone who participated in this project. It has been around 20 months since we conceived the idea, and the last 6 months or so have been crazy busy. But I'm very pleased with how the Multicart has turned out. It does almost everything I had originally envisaged, and in some cases more besides. Cheers

honestbob Joined: 03 Oct 2011 Posts: 188 Location: New Zealand	Multicart Label PDF Posted: Thu Mar 29, 2012 8:45 pm
	Hi All Here is the SC-3000 Multicart Label sheet for you to print your own labels. http://sc3000-multicart.com/downloads/SC3000Multicart_LabelSheet.pdf I did my best to make some nice sticky labels to ship with the Multicarts. Unfortunately the label paper I used was very disappointing as it smudges easily, is thin, and has poor color balance. So my new recommended setup is to print the labels on to glossy photo paper designed for your printer and using original inks. That looks a lot better and it less likely to smudge. (Check out the photo below) You can then use a glue stick to attach it to your cartridge shell. Cover the label with a tissue or clean piece of paper when you press it into place so you don't get your fingers all over it. And don't use too much glue as it may squidge around the edge of the label when you press it down. I'm much happier with that. The photo paper is a lot thicker, so it stays flat. And by using a glue stick you may even be able to lift the label later on if you need to unscrew the case. Cheers Multicart_Label_vs_PhotoPaper.jpg (122.98 KB) glossy photo paper vs crappy label paper (sc-3000 multicart)

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