Tengen 80008


Tech Specs:

Max. 64K PRG ROM.
Max. 64K CHR ROM.
74LS161 mapper.


This is an unique Tengen board- it is only used on one cart that I know of. Tetris. Anyways, there is not much to this one at all. It is essentially like CNROM with the ability to bank the PRG ROM (though on Tetris it is only 32K). There ARE bus conflicts.
Writing anywhere in 8000-FFFFh will load the banking register:

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

The C bits select an 8K CHR ROM page.
The P bit selects a 32K PRG ROM page.
Mirroring is pad-selectable.

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