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Making a Master System Flash/EEPROM cartridge
Posted: Tue Jan 29, 2013 6:17 pm
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Hi, I'm interested in making a reprogrammable cartridge for my Master System. I currently have Sonic 2 and After Burner available as donor cartridges (both 512k, After Burner should contain a mapper).
I could relatively easily get a 4 megabit EEPROM (Atmel AT29C040A), I understand I won't be using the entire capacity of it but it's the cheapest IC that's not an EPROM (which would require an expensive programmer/eraser) that I could get without resorting to international shipping (which is a pain in my country). I also have an Arduino which I plan on using to reprogram the chip, which seems rather feasible with a couple of shift registers, so that's also the programmer out of the way. My questions are more regarding the cartridge itself, however. Is the chip I picked compatible with the type of ROM the SMS uses? I have never done anything like this and have little to no knowledge about it, so any help would be appreciated. |
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Posted: Tue Jan 29, 2013 6:42 pm Last edited by TmEE on Tue Jan 29, 2013 6:51 pm; edited 1 time in total |
Shift registers are usable for EPROM, but flashes got elaborate command sequences and a shift register will make inputtingf them few hundred times slower... Look into parallel registers such as 74x374 / 74x574.
512KB can hold fair bit, and allow playing of majority of the library too :P |
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Posted: Tue Jan 29, 2013 6:45 pm |
After Burner is probably a safe bet. Check this list: http://www.smspower.org/Development/SMSPagingChips It says that it's likely After Burner has a 315-5235. Here are my instructions on converting Phantasy Star (but the same holds for any 4mbit game with 315-5235) to use an AM29F040: http://cgfm2.emuviews.com/smsflash.php As you can see the flash chip has 2 pins that function differently from the 32-pin mask ROM in Phantasy Star, so you have to do a little bit of wiring to accommodate that. All other pins have identical functions. It's a pretty easy modification to do IMO. |
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Posted: Tue Jan 29, 2013 6:59 pm |
I'll take a look into it, I'm at the moment trying to work with what I have an what I can easily get.
I saw your instructions and I also have Phantasy Star but I'd rather not ruin that one. Is there any chance of using Sonic 2 which is 512k without mapper chip instead? Would the mapper still work with a generic chip like the one I picked? The Atmel chip is the only Flash EEPROM I can find for sale in my country. |
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Posted: Tue Jan 29, 2013 7:08 pm |
No mapper chip, no go. Carts with no mapper have it integrated into the ROM. | |
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Posted: Tue Jan 29, 2013 7:12 pm |
Okay then, let's go with After Burner for now.
The mapper chip is a SEGA 315-5235 / 135U / 9023 Z28 The ROM chip is a SEGA MPR-11271-T / 4882-D950 / 9040EB1 Can I replace the ROM in this with the Atmel chip with a few or no pin replacements? Is there a diagram for the ROM chip? I can only find diagrams for the mappers. |
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Posted: Tue Jan 29, 2013 8:51 pm |
Can you clarify what you mean by "have it integrated into the ROM"? Does that mean they're using a chip with special logic, or is it just how the ROM data is laid out? |
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Posted: Tue Jan 29, 2013 9:17 pm |
ROM with special logic inside. They are not vanilla memory chips. | |
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Posted: Wed Jan 30, 2013 5:16 am |
Generally speaking all 4-megabit mask ROMs will have the same pinout, and the instructions I list for Phantasy Star compensate for the difference between those chips and the AM29F040. |
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Posted: Wed Feb 06, 2013 8:25 pm |
Hi! I developed a flash cart based on a card donor, using the AF29F040 I made an external ziff socket on the original cart, then I use an eeprom programmer to flash my games. I made some modifications and a lot of studies to make it works and now I can load EVERY game except the 1Mb roms like Sonic Chaos. I'm very happy to see on my beloved SMS games that I used to dream when I was young! :-) [img][/img] |
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Posted: Fri Feb 08, 2013 6:57 pm |
Thanks for the replies everyone. TmEE helped me with a schematic for a parallel-port EEPROM burner so I already have some plans for my cart.
I will be using After Burner (4mbit mapper) as the donor cart, with an Atmel AT29C040 4mbit Flash EEPROM chip. Due to a misplacement of my soldering iron (actually, my dad's), I won't be able to do anything until the next week. What I'll have to do is assemble the burner (4 ICs and a socket on a perfboard with LPT for data and USB for power) and solder a socket onto the After Burner cart. I'll check the pinout for the AM29F040 against my chip and work with Charles' instructions for the ROMs. Will report back as soon as I get something working. Again, thanks for the help! |
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Posted: Tue Aug 05, 2014 11:02 pm |
Sorry for the massive bump, but finally after all this time, I have succeeded!
I built my own EEPROM burner from an Arduino thanks to Tiido's help and after 3 days battling bugs and having to buy a new PSU for my Master System, I finally have a flashcart. |
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awesome
Posted: Wed Aug 06, 2014 7:38 am
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Congrats Svetlana, you did a perfect job!
Can you explain to me how did you do this project? Thanks! |
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Posted: Wed Aug 06, 2014 2:50 pm |
I started with Charles MacDonald's EEPROM cartridge guide which I linked earlier in this thread. Once I acquired the 4Mbit memory (in my case I got model AT29C040A, 4Mbit Flash EEPROM by Atmel), I used After Burner as a donor cartridge for its 4Mbit mapper, desoldering and socketing the original ROM noting that one of the pins must have its trace cut and rewired to another pin (I soldered a jumper on the back of my cart's PCB, doesn't show on the picture) After you have a socketed cart, the only thing to do is burn the ROM you want on the memory, plug it in and it'll work as that cartridge. However, since I didn't have a burner and I didn't want to spend a huge amount of money on one just for this project, Tiido helped me make my own. The first attempt was a parallel port burner, but since I have a 64bit system it was difficult to get it to work so I shelved the project until a couple of days ago, when I made a second attempt using an Arduino and its serial connection instead. It took me some time to code and debug burner software for it but eventually I got it working. Sadly I don't have any TVs in my room so the only screenshot from the SMS I could get was from my capture card, which I use to play games. |
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Posted: Wed Aug 06, 2014 3:57 pm |
Edited once by me.
This is an awesome project! Will it work on the Game Gear too? |
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Posted: Wed Aug 06, 2014 4:43 pm |
I have no experience at all with the Game Gear, but I imagine if it uses a similar mapper, you should be able to do something like this, ignoring the size difference. |
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Posted: Wed Aug 13, 2014 1:40 pm |
Cool, thanks! | |
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Posted: Thu Apr 06, 2017 5:49 pm |
Sorry for posting in this old thread. I need to know what was the cut and rewire of the memory. I am using the same memory (Atmel) and Mercs cartridge donor. How I have to do the rewire? I'm doing a 512KB reproduction. |
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Posted: Thu Apr 06, 2017 6:08 pm |
Follow Charles MacDonald's guide here: http://dreamjam.co.uk/emuviews/smsflash.php |
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Arduino EEPROM burner question
Posted: Tue May 02, 2017 3:13 pm
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First of all, thanks for sharing this project. It's exactly what I need. My question is not about how to wire/rewire the EEPROM pins, but, how you did the burner itself? I really been searching for weeks but I didn't find how to wire the EEPROM with the arduino and how to program my ROM into It. Sorry if I have ortographical mistakes. Thanks for your time and greetings from Argentina! |
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Posted: Fri May 05, 2017 10:44 pm |
Here's a writeup of my original project: http://mynameiser.in/post/94106321451/i-figured-the-eeprom-burner-deserved-a-pro... Here's the code I've written for it: https://github.com/Lana-chan/EEPROMDate/ It's not very user friendly. The wiring instructions are in the project's readme. |
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Posted: Sat May 27, 2017 4:56 pm |
This would be interesting to be able to carry out my new project for SMS | |
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Posted: Sat Aug 26, 2017 8:33 am |
The link seems to be dead now :-(. Where can I find it now? |
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Posted: Sun Sep 10, 2017 9:43 am |
Found some other guide for this, not sure where's the difference...
I also took After Burner as donor cartridge. I removed the ROM and replaced it with an AT29C040A. I also installed a ZIF socket and a switch to toggle between the original ROM layout and the one the Flash chip needs (just taking A18 from pin 1 instead of pin 31). With the original ROM the game starts up. Switching to Flash doesn't work, though, the SMS starts the BIOS game instead. Yes, the Flash was programmed ;-) (with After Burner as well, just to be sure). Is there any pin I have to pull down/up to gnd/Vcc? Maybe Pin 31 to Vcc? Currently it's floating. I don't know, where's the problem, can anybody help? |
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