Tool to compute checksums
Software
Compute internal checksums for PROM.
For SYSTEM 80 & 80A
and MA-216 sound card.
Checksums
All PROM use internal control mechanisms which allow to verify the integrity of the programs and data. For non-matching of the checksum with the contents of the memory, tests modes (of the CPU board or sound board) tests will indicate an anomaly.
If you want to edit or create a PROM, it is therefore necessary to have a tool to calculate these values. We created this software, from nothing, because of course there is no documentation on the subject.
Through analysis, we were able to determine where those values were located and how they were calculated. Difficult task, since the algorithms used are not standard and more vary according to the PROM. Especially for the PROM audio, where each model is a different case.
Our software
Written in Visual Basic for PC Windows, under its apparent simplicity hides in fact a complex programming.
It allows the calculation for the:
- SYSTEM PROM (U2 & U3) for the series 80 and 80A.
- Game PROM, all sizes (512, 1024, 2048) and for both SYSTEM 80 and 80A.
- PROM for audio board MA-216 (evolved board with SC-01).
Obsolescence
The "stand-alone" version of this program was discontinued at the end of 2016. It is now replaced by a new version, integrated in the ULTIMATE BENCH TEST software solution (for the NG bench test).
Distribution
This achievement is not publicly available, in any form whatsoever (free or paid).
