NEO-273



One 16-bit D-FF (to address a 128KiB S ROM) and one 20-bit D-FF (to address 8MiB of C ROMs) in one package. Later replaced by the NEO-CMC which performs the same function along with quite a few other things.

For cartridges that use this chip but have more than 8MiB of C ROM, extra bits were added using 7400 chips. An added LS74 (2 bits) in CHA256 boards for example increases the C ROM capacity from 8MiB to 32MiB (256M).

=Pinout=



Note that A4 of the C ROMs is missing since it bypasses the chip and comes straight from the cartridge edge. Same issue with A3 of the S ROM.