SMB2J - i want to make one

SMB2J - i want to make one
by gorgyrip on 2011-01-11 (#72591)

Hi,
I'm planning to make a smb2j on a cart.
I'm using 2 x 49f040 plcc32. I know that this chips are not the best choice, but they are the only one i have. i hope they will work.

As donor cart i used Super Mario Bros 3.

I'm using loopy's mm3 hack. the file's size 81,936.
I've used ucon64 to obtain the chr and prg files with this command:
ucon64 -s smb2j.nes

I don't have a programmer, but i have this:
http://www.ziegler.desaign.de/readplus.htm#GB_Flasher

and i made an adapter like this:
http://www.ziegler.desaign.de/c3cart.gif

So now the chips are programmed.

For the PRG rom, all the connections are pin per pin, except this:

49F040 ..........PRG
pin 1 (A18)--- hole 2
pin 2 (A16)--- hole 24
pin30 (A17)--- hole 1
pin24 (OE)--- GND

The BIG question: will this thing work? and where do i connect the WE pin for 49F040?

by Xious on 2011-01-13 (#72690)

I don't recall if there was a reason tat SMB2(J) is MMC3 and not CNROM and likewise, I'm not sure why I'm replying to this... Senseless generosity I guess...

49F040 ..........MMC3 Mapper Pin #
pin 1 (A18)--- 23
pin 2 (A16)--- 21
pin30 (A17)--- 25
(/CE)-----------26
(GND)----------28

If SMB3 uses the mask ROMs that I remember it using, the DIP pinout would be:

49F040 ..........512K DIP Pin #
pin 1 (A18)--- 2
pin 2 (A16)--- 24
pin30 (A17)--- 1
(/CE)-----------22
(GND)---------16

Alternatively:

49F040 ..........256K DIP Pin #
pin 1 (A18)--- NC
pin 2 (A16)--- 24
pin30 (A17)--- 1
(/CE)-----------22
(GND)---------16

You should read the Wiki and other data pages for more info... This is all documented here.

by gorgyrip on 2011-01-13 (#72694)

i did that and it's not working.
i think the problem is that i flashed the chips in the way: splet the rom to chr and prg and then directly flashed, without making the files bigger.

by tepples on 2011-01-13 (#72696)

If you don't double-up the PRG and CHR before you flash it to a larger chip, you'll need to ground any unused address lines. For example, if the result after split was 64 KiB, you'll need to ground A16 on up.

by gorgyrip on 2011-01-13 (#72706)

CHR is 16,384 and PRG is 65,536.
so all i need to do is lift pins A16, A17 and A18 for both 49f040 and connect them to ground?

the WE pin is connected to OE pin on both chips.

by tokumaru on 2011-01-13 (#72708)

Since 2 ^ 14 = 16384, for the CHR you only need 14 address lines, so A14 and up should be grounded. For the PRG, 2 ^16 = 65536, so A16 and up must be grounded. I believe /WE must be connected to +5V.

by gorgyrip on 2011-01-15 (#72743)

It works! It works!
Mega thanx to everyone!
I connected We to VCC, and the A points to gnd.