PCM: Difference between revisions
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[[File:crt_pcm.jpg|right|thumb|NEO-PCM chip found in a MVS cartridge. Picture courtesy of [[http://www.mvs-scans.com MVS-Scans]].]] | [[File:crt_pcm.jpg|right|thumb|NEO-PCM chip found in a MVS cartridge. Picture courtesy of [[http://www.mvs-scans.com MVS-Scans]].]] | ||
[[V ROM]] banking and multiplexing chip, found in AES and MVS [[cartridges]]. | [[V ROM]] banking and multiplexing chip, found in AES and MVS [[cartridges]], and on [[ROM-Only boards|ROM-only]] arcade boards. Used to multiplex V ROM (ADPCM-A and ADPCM-B) access to mixed-content ROM chips. | ||
[[NEO-PCM2]] can also be found in late cartridges and with [[NEO-YSA2]] | [[NEO-PCM2]] can also be found in late cartridges and with [[NEO-YSA2]]. | ||
On some [[cartridge | On some [[cartridge board]]s, V A20~V A22 can be used to select which of the 4 possible V ROMs to use (decoded by a LS139). | ||
=Pinout= | =Pinout= | ||
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OpenOffice Draw file: [[File:pcm.odg]] | OpenOffice Draw file: [[File:pcm.odg]] | ||
Has an inverting gate on pins 26 and 27. | |||
*SDPOE, SDROE, SDPMPX, SDRMPX: from the [[YM2610]] | *SDPOE, SDROE, SDPMPX, SDRMPX: from the [[YM2610]] | ||
*SDRAD0~SDRAD7: ADPCM-A | *SDRAD0~SDRAD7: ADPCM-A multiplexed bus part | ||
*SDPAD0~SDPAD7: ADPCM-B | *SDPAD0~SDPAD7: ADPCM-B multiplexed bus part | ||
*SDRA8,SDRA9,SDRA20~SDRA23: ADPCM-A address bus | *SDRA8,SDRA9,SDRA20~SDRA23: ADPCM-A address bus | ||
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*V D0~V D7: V ROM(s) data bus | *V D0~V D7: V ROM(s) data bus | ||
*V A0~V | *V A0~V A22: V ROM(s) address bus | ||
[[Category:Chips]] | [[Category:Chips]] | ||
Revision as of 21:09, 6 April 2012
V ROM banking and multiplexing chip, found in AES and MVS cartridges, and on ROM-only arcade boards. Used to multiplex V ROM (ADPCM-A and ADPCM-B) access to mixed-content ROM chips.
NEO-PCM2 can also be found in late cartridges and with NEO-YSA2.
On some cartridge boards, V A20~V A22 can be used to select which of the 4 possible V ROMs to use (decoded by a LS139).
Pinout
OpenOffice Draw file: File:Pcm.odg
Has an inverting gate on pins 26 and 27.
- SDPOE, SDROE, SDPMPX, SDRMPX: from the YM2610
- SDRAD0~SDRAD7: ADPCM-A multiplexed bus part
- SDPAD0~SDPAD7: ADPCM-B multiplexed bus part
- SDRA8,SDRA9,SDRA20~SDRA23: ADPCM-A address bus
- SDPA8~SDPA11: ADPCM-B address bus
- V D0~V D7: V ROM(s) data bus
- V A0~V A22: V ROM(s) address bus