MB-91 H

Board

Tech Specs:

Max. 32K PRG ROM.
Max. 32K CHR ROM.
74LS138
74LS175
MX8018-0002-A lockout replacement

Description:

Seems to be an earlier revision of the NINA-06 board. It uses the lockout replacement chip, and had pads on it for selecting a 27256 or 27512 ROM in both CHR and PRG positions.

There is only one register on this cart. It maps in kinda strangely.

4100-41FF, 4300-43FF, 4500-45FF ... 5F00-5FFF

7       0
---------
xxxx PCCC

C: Selects an 8K CHR ROM bank
P: Selects a 32K PRG ROM bank

CHR and PRG banks are unknown on startup.  Mirroring is hardwired on cart.