V ROM: Difference between revisions
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In early games, the ADPCM-A and ADPCM-B data was stored in separate V ROMs. Later, the {{Chipname|PCM}} demultiplexer chip was made to allow both types of data to be mixed in the same ROM(s). | In early games, the ADPCM-A and ADPCM-B data was stored in separate V ROMs. Later, the {{Chipname|PCM}} demultiplexer chip was made to allow both types of data to be mixed in the same ROM(s). | ||
The TC5332204 mask ROMs have a similar pinout to the 27C322 EPROMs. The only difference is that they're set to byte mode only: | The TC5332204 mask ROMs have a similar pinout to the 27C322 EPROMs. The only difference is that they're set to byte mode only: half of the data output pins are unused. Pin 30 (Q15) is used as the address lowest bit. | ||
==Speed== | ==Speed== | ||
Latest revision as of 03:27, 12 April 2018
The V(oice ?) ROMs contain the ADPCM audio samples in cartridges.
In early games, the ADPCM-A and ADPCM-B data was stored in separate V ROMs. Later, the PCM demultiplexer chip was made to allow both types of data to be mixed in the same ROM(s).
The TC5332204 mask ROMs have a similar pinout to the 27C322 EPROMs. The only difference is that they're set to byte mode only: half of the data output pins are unused. Pin 30 (Q15) is used as the address lowest bit.
Speed
- V A ROMs minimum speed: any will do (>2µs).
- V B ROMs minimum speed: 250ns (see YM2610 bus timing).