NEO-E0: Difference between revisions
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=68k vector table swapping= | =68k vector table swapping= | ||
The 68k vector table is selected | The 68k vector table seen by the 68k is selected by writing to {{Reg|REG_SWPROM}} (table from the game) or {{Reg|REG_SWPBIOS}} (table from the [[system ROM]]). | ||
A22Z and A23Z are used in place of A22 and A23 to make the address appear to address decoding chips as a system ROM access instead of a [[P ROM]] access. | A22Z and A23Z are used in place of A22 and A23 to make the address appear to address decoding chips as a system ROM access instead of a [[P ROM]] access. | ||
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|$000000~$00007F||$C00000~$C0007F||$000000~$00007F | |$000000~$00007F||$C00000~$C0007F||$000000~$00007F | ||
|- | |- | ||
|$000080~$BFFFFF||colspan=2| | |$000080~$BFFFFF||colspan=2|No change | ||
|- | |- | ||
|$C00000~$C0007F||$000000~$00007F||$C00000~$C0007F | |$C00000~$C0007F||$000000~$00007F||$C00000~$C0007F | ||
|- | |- | ||
|$C00080~$FFFFFF||colspan=2| | |$C00080~$FFFFFF||colspan=2|No change | ||
|} | |} | ||
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|} | |} | ||
==MV2F @ E1 pinout (to be confirmed)== | ==MV2F @ E1 pinout (to be confirmed) and AES== | ||
{| | {| | ||
Latest revision as of 07:19, 18 July 2022
| |
| Package | QFP64R |
| Manufacturer | 
|
| First use | 1991 ? |
| Used on | NEO-AES3-3 ... |
Just a 24-bit buffer and logic for 68k vector table swapping.
68k vector table swapping
The 68k vector table seen by the 68k is selected by writing to REG_SWPROM (table from the game) or REG_SWPBIOS (table from the system ROM).
A22Z and A23Z are used in place of A22 and A23 to make the address appear to address decoding chips as a system ROM access instead of a P ROM access.
The VEC signal comes from the 74H259 system latch.
| Address | Maps to | |
|---|---|---|
| VEC = 0 | VEC = 1 | |
| $000000~$00007F | $C00000~$C0007F | $000000~$00007F |
| $000080~$BFFFFF | No change | |
| $C00000~$C0007F | $000000~$00007F | $C00000~$C0007F |
| $C00080~$FFFFFF | No change | |
Verilog from User:Kyuusaku:
{A23Z,A22Z} = A[23:22] ^ 2{~|{A[21:7],^A[23:22],VEC}}
Pinouts
Input to output map
- 64 -> 5
- 1 -> 6
- 2 -> 7
- 3 -> 8
- 4 -> 9
- 15 -> 11
- 16 -> 12
- 17 -> 13
- 18 -> 14
- 19 -> 22
- 20 -> 23
- 21 -> 24
- 31 -> 27
- 32 -> 28
- 33 -> 29
- 34 -> 30
- 36 -> 39
- 37 -> 40
- 38 -> 41
- 48 -> 43
- 49 -> 44
- 50 -> 45
- 51 -> 46
- 52 -> 47
- 53 -> 55 if VEC is high
- 54 -> 56 if VEC is high
Console
On the AES, the AND gate is used to make /SROMOE from (/SROMOEL AND /SROMOEU).
MV2B & MV2-01 @ H7 pinout
- 55 = sPCK1B
- 56 = sPCK2B
P_bus buffer
MV2B @ G2 pinout
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OpenOffice Draw file: File:Neo-e0 mv2b G2.odg |
|
MV2B @ F7 pinout
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OpenOffice Draw file: File:Neo-e0 mv2b F7.odg |
Acts just as a buffer.
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MV2F @ E1 pinout (to be confirmed) and AES
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OpenOffice Draw file: File:Neo-e0.odg |
|
