nesdev.org

Just researching donor boards more and it seems as if the donor board itself is not what matters. I was trying to figure out the big difference in boards such as TLROM-03, -02, and so on.

http://nesdev.com/rom.txt

From that sheet it appears as if the boards themselves are not what matters most but what chips are on them and what they hold.

Such as a TLROM -03 board containing a MMC3C chip supports Up to 256K of C-ROM and 512K of P-ROM

However a TKROM-10 also contains a MMC3C chip and NES-TKROM-10 and supports 8K battery-backed SRAM, 256K of C-ROM, and 512K of P-ROM.

So one would believe that would be a suitable donor cart as well, it just has save capabilities so you wouldn't want to waste on a game that didn't use save.

I am still a little confused as to the board revisions and what role they play as in TLROM-03, -02, and so on.

In theory it appears the board type is not what matters though is that correct? As long as mapper is correct and the C-Rom and P-Rom have the capacity you need then it should be a suitable donor?

So like Gold Medal challenge is a NES-TKROM-10 so that would be a suitable donor for any TLROM game, but it would be wasting the save capabilities.

I assume in something like Tetris 2 that is NES-TSROM-08 it would require programming differently? Due to the address space remark. Or would that not work for TLROM.

NES-TSROM-[04,06,07]

8K of WRAM mapped in at 6000-7FFF in the CPU's address space. Up to
256K of C-ROM and 512K of P-ROM.

The board and chips both matter, though most boards are only designed for one chip.

If you have the right chip and the wrong board, you can modify the board with extra wires and stuff to correct the difference. Some boards are also cross-compatible to a small extent. (The board is just wiring to support the chips on it. You can always rewire.)

The board is basically the wiring, different boards are wired differently, though similar boards sometimes only differ by a single address line or other subtle changes.

you could certainly cut the traces on a board and basically use it as just a cart edge then it doesn't much matter as long as you can wire up something the nes understands

Definitely matters. Especially for wiring

Well what I was getting at is boards are designed based on the components they have. I guess they go hand in hand. However A board that houses a mmc3c as compared to a board that is mmc3b would be identical correct? However the mappers are not and depending on whether it is sharp or not will depend on whether you have problems. You could easily swap the mappers to each board and they would work fine right?

Just seems to me the components on the board are what matters most.

icemanxp300 wrote:However A board that houses a mmc3c as compared to a board that is mmc3b would be identical correct?

No.

Just as an example, a game designed to run on a board like TQROM, TR1ROM, TKROM, or TLSROM won't work properly on TLROM. Just having a MMC3 isn't enough.

• TQROM has additional logic to use both CHR-RAM and CHR-ROM.
• TR1ROM is wired for 4-screen mirroring, so the mirroring control in the MMC3 does nothing.
• TKROM has PRG-RAM.
• TLSROM uses a different MMC3 register to control mirroring.

In all of these cases, you could modify a TLROM board, but it's far easier to use a donor board that is similar or identical to the one the game originally came on.

In the end it boils down to your knowledge level.

If you know the NES hardware well enough you can take a TLROM and make it do things like 4screen (Gauntlet) and even add WRAM.

So I'd say if you know what you are doing you could make a Final Fantasy 3 reproduction out of a TLROM without need to destroy a Super Mario Bros2 cartridge. (just to mention a example of donor)


My TLROM modded board doesn't look nice but works great... hehe