Okay, I traced the signal on both PRG ROM and CHR ROM, so I get the pinout of MMC5 ROMs. However as :
- The pins on the MMC5 are really tiny, it's easy to get the count wrong
- I partially relied on existing MMC5 pinous that exists on the internet (Kevin Horton's docs)
I cannot guarantee that anything is 100%, I only belive it should be correct.
PRG ROM pinout
Code:
---U---
A17 - |01 32| - +5V
A18 - |02 31| - /OE (MMC5 pin 74)
A15 - |03 30| - A19 (no games uses this ?)
A12 - |04 29| - A14
A7 - |05 28| - A13
A6 - |06 27| - A8
A5 - |07 26| - A9
A4 - |08 25| - A11
A3 - |09 24| - A16
A2 - |10 23| - A10
A1 - |11 22| - GND (very likely /CE)
A0 - |12 21| - D7
D0 - |13 20| - D6
D1 - |14 19| - D5
D2 - |15 18| - D4
GND - |16 17| - D3
-------
CHR ROM pinout :
Code:
---U---
A17 - |01 32| - +5V
(not sure) A18 - |02 31| - /OE (PPU /RD)
A15 - |03 30| - A19 (no games uses this ?)
A12 - |04 29| - A14
A7 - |05 28| - A13 (from mapper)
A6 - |06 27| - A8
A5 - |07 26| - A9
A4 - |08 25| - A11
A3 - |09 24| - A16
A2 - |10 23| - A10
A1 - |11 22| - PPU A13 (very likely /CE)
A0 - |12 21| - D7
D0 - |13 20| - D6
D1 - |14 19| - D5
D2 - |15 18| - D4
GND - |16 17| - D3
-------
So yeah what I find is pretty much analogus to what BriPro says, and a little different from regular NES pinouts. If A19 pins are really A19, this would confirm that regular EKROM boards can support up to 1024KB PRG + 1024KB CHR without any hardware "tricks", at the cost to have different pinout for smaller sizes than other NES carts.
PRG ROMs gets PRG ROMs with 2 enable signals, unlike ROMs on regular NES board for sizes 128KB-512KB, but like regular EPROMs and NES boards with smaller PRG sizes (16KB-64KB), and aside of that it looks really similar to regular boards.