NES-CNROM

Cartridge Board

What Is It?

A discrete logic Nintendo-made board.
Max 32K of PRG ROM
Max 32K CHR ROM
74161.
Note: this board has bus conflicts.

The Tech:

The LS161 acts as a latch. It latches D0 and D1. Writing anywhere in the 8000h- FFFFh range will set this latch using the above data lines.

7  bit  0
---- ----
xxxx xxCC

The C bits select an 8K CHR ROM page.


Mirroring is hardwired on the cart.