MV1A

Description
A strangely designed MVS board which uses some chips found in the NeoGeo CD. Maybe allowed SNK to cut costs by using chips for both systems.

PALs
See MV1A PALs.

Main Board


list:
 * GA4: 68k bidirectional palette access
 * GA7: Read P1 and P2 inputs
 * GA8: Only half used, read REG_STATUS_B
 * GA9: 68k/Z80 communication
 * GA11: 68k data bus bidirectional buffer

Others:
 * U10: 68k to Z80 latch, clear = SDZ80CLR (NEO-D0 44), clock = SDW (SNK1A 22, NEO-D0 33)
 * U11: Z80 to 68k latch, no clear, clock = SDZ80W (NEO-D0 43)
 * U3:
 * 3(RAM4 22) = SNK1B-4 OR MGA-51
 * 6(RAM3 22) = SNK1B-4 OR MGA-53
 * 8(U4 1) = SNK1B-4 OR MGA-52
 * 11(U4 4) = SNK1B-4 OR MGA-54
 * U2:
 * 3(Cart) = ROMOEL OR MGA-51
 * 6(Cart) = ROMOEL OR MGA-53
 * 8(Cart) = ROMOEL OR MGA-52
 * 11(Cart) = ROMOEL OR MGA-54
 * U3:
 * 3(Cart) = ROMOEU OR MGA-51
 * 6(Cart) = ROMOEU OR MGA-53
 * 8(Cart) = ROMOEU OR MGA-55
 * 11(Cart) = ROMOEU OR MGA-72



Slot Board