View source for PC10 ROM-Images

Playchoice 10 ROM images can be stored in two formats:

== iNES Format ==

PC10 games in [[iNES]] format are indicated by Bit1 of Byte 7 of the iNES header. If the flag is set, then the file should contain some additional entries after the PRG ROM and CHR ROM areas:
* 8Kbyte INST ROM (containing data and Z80 code for instruction screens)
* 16 bytes RP5H01 PROM Data output (needed to decrypt the INST ROM)
* 16 bytes RP5H01 PROM CounterOut output (needed to decrypt the INST ROM) (usually constant: 00,00,00,00,FF,FF,FF,FF,00,00,00,00,FF,FF,FF,FF)
The two required PROM sections are missing in older ROM images. A tool for upgrading such incomplete dumps can be found at http://problemkaputt.de/pc10make.zip

Note: Some very old ROM images don't have the PC10 flag set in the header, and, instead, they declare the 8K INST ROM as an additional CHR ROM bank.

== MAME Format ==

Instead of using a single ROM image file, MAME stores all ROM, EPROM, and PROM chips in separate files.

The PROM data is typically stored in a file called "security.prm". It contains only the 16 Data bytes (not the CounterOut bytes). All bits in the PROM file are inverted, and the bit ordering is reversed: bit0 (the first bit of the PROM's serial bitstream) is stored in bit7 of the 1st byte of the file).

== PC10 Emulators ==

The iNES format is used by no$nes. The MAME format is used by MAME.

[[Category:File formats]]