NES-CPROM (no HVC-CPROM known) is a particular Nintendo cartridge board which uses discrete logic to provide up to four 4 KB banks of CHR RAM. The iNES format assigns mapper 13 to this board. Only Videomation, a paint program for NES, is known to use it.
7 bit 0 ---- ---- xxxx xxCC || ++- Select 4 KiB CHR RAM bank for PPU $1000-$1FFF
The CPROM board uses a 74HC161 (4-bit latch) and a 74HC08 (quad 2-input AND gate), with a 74HC04 (hex inverter) to unify the two RAMs.
Categories: Nintendo licensed mappers, Mappers with bus conflicts, In NesCartDB, Mappers with CHR RAM, Discrete logic mappers