Forums

Sega Master System / Mark III / Game Gear
SG-1000 / SC-3000 / SF-7000 / OMV
Home - Forums - Games - Scans - Maps - Cheats - Credits
Music - Videos - Development - Hacks - Translations - Homebrew

View topic - After Burner (JP) with split ROM

Reply to topic
Author Message
  • Joined: 08 Feb 2008
  • Posts: 75
  • Location: Slovakia
Reply with quote
After Burner (JP) with split ROM
Post Posted: Sun Apr 10, 2011 8:10 pm
Hello!
On Enri's site is an interresting schematics of AfterBurner (4Mb) Japanese SMS cartridge that uses two rom chips instead of American release, which uses only one to hold the game data.
http://www2.odn.ne.jp/~haf09260/Mark3/M34m-0.png
*EDIT* http://www43.tok2.com/home/cmpslv/Mark3/M34m-0.png

Since I wasn't able to find japanese alternative AfterBurner rom, just one with the [UE] tag, I guess that Japanese counterpart uses the same rom as the American one.
But something's bothering me - adress lines of those two rom chips are connected to the connector's pins in a strange manner, A0 goes to A1, A1 to A2 and so on... The pin called "D15/A-1" goes to A0.
Is the adress lines numbering wrong or can somebody tell me what does the "D15/A-1" pin mean? If I'm to adapt 27C040 (4Mbit) eprom to this cartridge, what should I connect to the A0 pin on the connector?
And also, are there really two OE pins on those rom chips? Shouldn't be there CE written on the pin 12?
As I understand, the game is just splitted to two parts (even and odd bytes). So connecting just one eprom shouldn't be a problem...
Any help appreciated! (And sorry if this is already somewhere on the forum, I couldn't find it...)
M34m-0.png (11.36 KB)
Attachment fairy
M34m-0.png

  View user's profile Send private message Visit poster's website
  • Site Admin
  • Joined: 19 Oct 1999
  • Posts: 12878
  • Location: London
Reply with quote
Post Posted: Sun Apr 10, 2011 8:40 pm
I split it to a new topic anyway, I think it is worth it :)

It looks a lot like the game is as you say split odd/even bytes between two ROMs, supporting this with the extra /CE pins on the mapper. Enri's labelling of "A-1" seems strange to me, I don't see that the ROM should care about that.

The mapper chips all seem to have combined /CE and /OE.

I updated the wiki with the new pin info.

Are you trying to put an EPROM in the After Burner JP cartridge? I guess you'd need to either put two or do some substantial work to rewire it as a single-chip cartridge.
  View user's profile Send private message Visit poster's website
  • Joined: 08 Feb 2008
  • Posts: 75
  • Location: Slovakia
Reply with quote
Post Posted: Sun Apr 10, 2011 8:55 pm
Last edited by jpx072 on Mon Apr 11, 2011 5:15 am; edited 1 time in total
I don't care about heavy rewiring (the original ROMs have pinouts totally different from JEDEC anyway) so I will hold to the one-chip-solution.
If the CE and OE are combined, why are there two OE pins on both rom chips?
The adaptation of the American After Burner is simple, no rewiring required (as far as I remember, I was doing this a long time ago...), I have to look on that one again and probably connect it exactly as that one is.
  View user's profile Send private message Visit poster's website
  • Joined: 28 Sep 1999
  • Posts: 1141
Reply with quote
Post Posted: Mon Apr 11, 2011 12:27 am
Quote
Is the adress lines numbering wrong or can somebody tell me what does the "D15/A-1" pin mean? If I'm to adapt 27C040 (4Mbit) eprom to this cartridge, what should I connect to the A0 pin on the connector?


Some 16-bit ROMs work in a 16-bit word or 8-bit byte mode, depending on an input pin (usually "/BYTE" that is tied to ground). In byte mode, pin D15 becomes the least significant address bit, which is A-1 (A minus one). So A0 is the next highest one, then A1, etc.

In the schematic the ROM is in byte mode so Z80 A0 goes to A-1, Z80 A1 goes to A0, Z80 A2 goes to A1, etc, and that is correct.

Quote
And also, are there really two OE pins on those rom chips? Shouldn't be there CE written on the pin 12?


Pin 10 is /OE and pin 12 is /CE, though in this case of read-only memory you can use them interchangeably or as the same thing.

Quote

As I understand, the game is just splitted to two parts (even and odd bytes). So connecting just one eprom shouldn't be a problem...


Not quite, the game uses two 128Kx16 EPROMs in byte mode to make 512K total, and CE1 from the mapper enables the first 256K, CE2 enables the next 256K.
  View user's profile Send private message Visit poster's website
  • Joined: 08 Feb 2008
  • Posts: 75
  • Location: Slovakia
Reply with quote
Post Posted: Mon Apr 11, 2011 5:15 am
Thank you Charles, I was hoping for an explanation this good! (This would also help me in other projects involving 16-bit roms).

SO after all it seems that using two 16-bit Eproms should be less problematic and would stick better to the original...
[but would require a lot more rewiring when I'm hoping to use two 8-bit eproms (27C020) instead of two 16-bit (my programmer's limitation to 8-bit and 32 pins max).]

As I see it, the only difference by using only one Eprom (512Kbyte) should be to connect the CE pin of the Eprom to pin 15 (CE0) on the mapper, and also using pin 14 of the mapper to adress A18 of the Eprom.
  View user's profile Send private message Visit poster's website
  • Joined: 28 Sep 1999
  • Posts: 1141
Reply with quote
Post Posted: Mon Apr 11, 2011 5:55 pm
Quote
As I see it, the only difference by using only one Eprom (512Kbyte) should be to connect the CE pin of the Eprom to pin 15 (CE0) on the mapper, and also using pin 14 of the mapper to adress A18 of the Eprom.


Yep that sounds good to me.

So you actually have one of these After Burner cartridges with two 16-bit ROMs? Any chance you could take a picture of the PCB before modifying it?
  View user's profile Send private message Visit poster's website
  • Joined: 08 Feb 2008
  • Posts: 75
  • Location: Slovakia
Reply with quote
Post Posted: Mon Apr 11, 2011 7:16 pm
Yes I have one and of course I will post scans of it (tomorrow), roms are already out so the wiring is nicely visible. I still can't decide how to do it, if I'm going to use the existing socket, or take wires out and place the Eprom next to the PCB.
Jpx out
  View user's profile Send private message Visit poster's website
  • Joined: 08 Feb 2008
  • Posts: 75
  • Location: Slovakia
Reply with quote
Post Posted: Tue Apr 12, 2011 5:09 am
Last edited by jpx072 on Wed Apr 13, 2011 9:58 am; edited 1 time in total
Here are the scans, the scanner isn't very good, but if requested I can make some high quality photos...

EDIT
I have added two gifs with wires highlighted, it's done only in Paint (for my own needs) but it may prove usefull to someone... (EDIT2 - updated one of them to correctly show all the wires)
AfterBurnerSMS(J)_front.jpg (1001.02 KB)
Front side
AfterBurnerSMS(J)_front.jpg
AfterBurnerSMS(J)_back.jpg (1010.19 KB)
Back side
AfterBurnerSMS(J)_back.jpg
AfterBurnerSMS(J)_back.GIF (243.88 KB)
Wires back
AfterBurnerSMS(J)_back.GIF
AfterBurnerSMS(J)_front.GIF (213.74 KB)
Wires front
AfterBurnerSMS(J)_front.GIF

  View user's profile Send private message Visit poster's website
  • Joined: 28 Sep 1999
  • Posts: 1141
Reply with quote
Post Posted: Tue Apr 12, 2011 4:23 pm
jpx072 wrote
Here are the scans, the scanner isn't very good, but if requested I can make some high quality photos...


Thanks for the nice pictures! Very interesting cart.

What did the ROMs look like? If you don't have them anymore that's OK, I'm just curious if they had a MPR/EPR part number on them, if they were plastic or ceramic, maybe a manufacturer's logo, etc.
  View user's profile Send private message Visit poster's website
  • Site Admin
  • Joined: 19 Oct 1999
  • Posts: 12878
  • Location: London
Reply with quote
Post Posted: Tue Apr 12, 2011 5:07 pm
Enri's schematic has the MPR numbers - 11272 and 11273.
  View user's profile Send private message Visit poster's website
  • Joined: 28 Sep 1999
  • Posts: 1141
Reply with quote
Post Posted: Tue Apr 12, 2011 6:26 pm
Maxim wrote
Enri's schematic has the MPR numbers - 11272 and 11273.


Oh yeah, but I'm curious if his was the same version. It probably is.
  View user's profile Send private message Visit poster's website
  • Joined: 08 Feb 2008
  • Posts: 75
  • Location: Slovakia
Reply with quote
Post Posted: Tue Apr 12, 2011 7:53 pm
Oh yes I still have them (but not here where I am now), in case I would want to revert the cartridge to its original state. I remember the exact numbers 11272 and 11273 on those roms but I don't remember more, when I get to them, I will post a photo!
  View user's profile Send private message Visit poster's website
  • Joined: 08 Feb 2008
  • Posts: 75
  • Location: Slovakia
Reply with quote
Post Posted: Wed Apr 13, 2011 7:18 am
I have edited the 315-5235 mapper pinout diagram in the Development "mapper pinouts" page - the CE pins should be numbered CE0,CE1 and CE2 (like 315-5365) to avoid further confusion when someone's comparing it with Enri's schematics.

I don't know who Enri is, but his page is really great, and since he's a member here, somebody with some Japanese language skills should ask him for permision to add his schematics to the Development part of Smspower. For example to create a separate part for Japanese SMS. (that is, if those schematics aren't already somewhere, I haven't been around for some time)
I have checked his schematics for After Burner (JP) cartridge and I can confirm it's flawlessnes.
Also there's a great list of Japanese games with rom sizes, numbers and mapper info, I was able to create a nice table (needs translation!) out of that info (see the attachment).


(And HERE's another of my "lazy at work" pictures of the cartridge)
table.xls (27 KB)

  View user's profile Send private message Visit poster's website
  • Site Admin
  • Joined: 19 Oct 1999
  • Posts: 12878
  • Location: London
Reply with quote
Post Posted: Wed Apr 13, 2011 9:19 am
I merged the ROM part numbers into Development/ROMPartNumbers.
  View user's profile Send private message Visit poster's website
  • Joined: 08 Feb 2008
  • Posts: 75
  • Location: Slovakia
Reply with quote
Post Posted: Wed Apr 13, 2011 9:50 am
Wow great work! I was already thinking where to put the info from that table :)

EDIT: I've attached the photo of those AfterBurner(JP) rom chips!
Afterburnerroms.jpg (170.07 KB)
Afterburnerroms.jpg

  View user's profile Send private message Visit poster's website
  • Site Admin
  • Joined: 19 Oct 1999
  • Posts: 12878
  • Location: London
Reply with quote
Post Posted: Wed Apr 13, 2011 10:37 am
Feel free to make a wiki page for the board schematic. We could add a schematics sub-section or it could go in the "hardware images" section.
  View user's profile Send private message Visit poster's website
  • Joined: 28 Sep 1999
  • Posts: 1141
Reply with quote
Post Posted: Wed Apr 13, 2011 4:51 pm
jpx072 wrote
Wow great work! I was already thinking where to put the info from that table :)

EDIT: I've attached the photo of those AfterBurner(JP) rom chips!


Thanks! Just want I wanted to see. :D
  View user's profile Send private message Visit poster's website
  • Joined: 08 Feb 2008
  • Posts: 75
  • Location: Slovakia
Reply with quote
Post Posted: Tue Feb 06, 2018 8:45 pm
Hey guys! It's been 7 years since I started this project, but life is like that, you never know what gets in the way of your goals.

Anyway I believe there are already tons of finished rewritable carts for japanese SMS, but I wanted to show you what I've accomplished today.
It's a 512kb eprom cart, fully working, actually playing the awesome Sonic1 with FM sound mod.

I only did what we have discussed here 7 years ago, so the assumptions were okay, everything works like expected. I used only one 27c040 eprom.

I am happy :-D
1517949353333image.JPG (600.16 KB)
Front
1517949353333image.JPG
1517949341575image.JPG (628.82 KB)
Back
1517949341575image.JPG

  View user's profile Send private message Visit poster's website
  • Joined: 05 Nov 2014
  • Posts: 254
  • Location: Auckland - NZ
Reply with quote
Post Posted: Fri Feb 09, 2018 9:58 pm
Nice job! Glad it all worked out
  View user's profile Send private message
Reply to topic



Back to the top of this page

Back to SMS Power!