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Most names come from the official [[schematics]]. | |||
=Clocks= | |||
{| class="regdef" | |||
|'''Name''' | |||
|'''Description''' | |||
|'''Type''' | |||
|'''Comes from''' | |||
|'''Fault consequence''' | |||
|- | |||
|24M | |||
|24MHz master clock | |||
|[[Clock]] | |||
|{{Chipname|NEO-D0}} | |||
|Nothing works, no video at all | |||
|- | |||
|12M | |||
|12MHz clock (24/2) non-inverted | |||
|Clock | |||
|{{Chipname|NEO-D0}} | |||
|Bad graphics | |||
|- | |||
|8M | |||
|8MHz clock (24/3) non-inverted | |||
|Clock | |||
|{{Chipname|LSPC}} | |||
|No sound | |||
|- | |||
|6MB | |||
|6MHz clock (24/4) inverted | |||
|Clock | |||
|{{Chipname|NEO-D0}} | |||
|Black screen ? | |||
|- | |||
|4M | |||
|4MHz clock (24/6) non-inverted | |||
|Clock | |||
|{{Chipname|LSPC}} | |||
|No sound | |||
|- | |||
|4MB | |||
|4MHz clock (24/6) inverted | |||
|Clock | |||
|{{Chipname|LSPC}} + inverter | |||
|? | |||
|- | |||
|1MB | |||
|'''3MHz''' (!) clock (24/8) inverted | |||
|Clock | |||
|{{Chipname|NEO-D0}} | |||
|? | |||
|- | |||
|68KCLK | |||
|12MHz clock (24/2) non-inverted | |||
|Clock | |||
|{{Chipname|NEO-D0}} | |||
|[[Click of death]] | |||
|- | |||
|68KCLKB | |||
|12MHz clock (24/2) inverted | |||
|Clock | |||
|{{Chipname|NEO-D0}} | |||
|Bad ADPCM-B instruments in games using {{Chipname|PCM}} | |||
|} | |||
=CPU ([[68k]])= | |||
{| class="regdef" | |||
|'''Name''' | |||
|'''Description''' | |||
|'''Type''' | |||
|'''Comes from''' | |||
|'''Fault consequence''' | |||
|- | |||
|A1~A23 | |||
|[[68k]] address bus | |||
|Address | |||
|{{Chipname|68k}} | |||
|Click of death | |||
|- | |||
|A22I,A23I | |||
|Altered address lines for [[68k vector table]] swap | |||
|Address | |||
|{{Chipname|NEO-E0}} | |||
|Probably click of death | |||
|- | |||
|/AS | |||
|68k Address Strobe | |||
|Control | |||
|{{Chipname|68k}} | |||
|Probably click of death | |||
|- | |||
|D0~D15 | |||
|68k data bus | |||
|Data | |||
|Multiple | |||
|Click of death | |||
|- | |||
|/DTACK | |||
|68k Data Transmit ACKnowledge (see [[wait cycle]]) | |||
|Control | |||
|{{Chipname|NEO-C1}} | |||
|Click of death ? | |||
|- | |||
|/PORTADRS | |||
|$200000-$2FFFFF (P2 ROM/[[PRO-CT0|Security chip]]) any access | |||
|Control | |||
|{{Chipname|NEO-C1}} | |||
|Game freezes, bad graphics | |||
|- | |||
|/PORTOEL | |||
|$200000-$2FFFFF (P2 ROM/Security chip) odd byte read | |||
|Control | |||
|{{Chipname|NEO-C1}} | |||
|Game freezes, bad graphics | |||
|- | |||
|/PORTOEU | |||
|$200000-$2FFFFF (P2 ROM/Security chip) even byte read | |||
|Control | |||
|{{Chipname|NEO-C1}} | |||
|Game freezes, bad graphics | |||
|- | |||
|/PORTWEL | |||
|$200000-$2FFFFF (P2 ROM/Security chip) odd byte write | |||
|Control | |||
|{{Chipname|NEO-C1}} | |||
|Game freezes, [[multiplayer]] comm. error | |||
|- | |||
|/PORTWEU | |||
|$200000-$2FFFFF (P2 ROM/Security chip) even byte write | |||
|Control | |||
|{{Chipname|NEO-C1}} | |||
|Game freezes, bad graphics | |||
|- | |||
|/PWAIT0, /PWAIT1 | |||
|Delay configuration for [[P ROM|P2 ROM]] reads, see [[wait cycle]] | |||
|Control | |||
|{{Chipname|NEO-C1}} | |||
|Game freezes (very likely) | |||
|- | |||
|R/W | |||
|68k Read/Write | |||
|Control | |||
|{{Chipname|68k}} | |||
|Click of death | |||
|- | |||
|/ROMOE | |||
|$000000-$0FFFFF ([[P ROM|P1 ROM]]) read | |||
|Control | |||
|{{Chipname|NEO-C1}} + AND | |||
|Game doesn't start | |||
|- | |||
|/ROMOEL | |||
|$000000-$0FFFFF (P1 ROM) odd byte read | |||
|Control | |||
|{{Chipname|NEO-C1}} | |||
|Game doesn't start | |||
|- | |||
|/ROMOEU | |||
|$000000-$0FFFFF (P1 ROM) even byte read | |||
|Control | |||
|{{Chipname|NEO-C1}} | |||
|Game doesn't start | |||
|- | |||
|/ROMWAIT | |||
|Add 1-cycle delay for P1 ROM reads | |||
|Control | |||
|{{Chipname|NEO-C1}} | |||
|Game freezes (unlikely) | |||
|- | |||
|/SROMOE | |||
|$C00000-$CFFFFF ([[System ROM]]) read | |||
|Control | |||
|{{Chipname|NEO-E0}} | |||
|Click of death | |||
|- | |||
|/SROMOEL | |||
|$C00000-$CFFFFF (System ROM) odd byte read | |||
|Control | |||
|{{Chipname|NEO-C1}} | |||
|Click of death | |||
|- | |||
|/SROMOEU | |||
|$C00000-$CFFFFF (System ROM) even byte read | |||
|Control | |||
|{{Chipname|NEO-C1}} | |||
|Click of death | |||
|- | |||
|} | |||
=Graphics= | |||
{| class="regdef" | |||
|'''Name''' | |||
|'''Description''' | |||
|'''Type''' | |||
|'''Comes from''' | |||
|'''Fault consequence''' | |||
|- | |||
|2H1 | |||
|[[S ROM]] A3 | |||
|Address | |||
|{{Chipname|LSPC}} | |||
|Bad fix graphics | |||
|- | |||
|CA4 | |||
|[[C ROM]]s A4 | |||
|Address | |||
|{{Chipname|LSPC}} | |||
|Bad sprite graphics | |||
|- | |||
|C* or CR0~CR31 | |||
|C ROMs data bus (2*16bits), data for one 8-pixels line | |||
|Data | |||
|{{Chipname|C ROM}} | |||
|Bad sprite graphics | |||
|- | |||
|FIXD0~FIXD7 | |||
|[[Fix layer]] data bus, data for 2 pixels | |||
|Data | |||
|{{Chipname|S ROM}} | |||
|[[Graphic glitches|Static vertical lines]], solid color screen | |||
|- | |||
|P0~P23 | |||
|Multiplexed [[P bus]] | |||
|Muxed | |||
|Multiple | |||
|Garbled or absent graphics | |||
|- | |||
|PA0~PA11 | |||
|[[Palette RAM]] address bus | |||
|Address | |||
|{{Chipname|NEO-B1}} | |||
|Bad colors, snow, black screen | |||
|} | |||
=Misc.= | |||
{| class="regdef" | |||
|'''Name''' | |||
|'''Description''' | |||
|'''Type''' | |||
|'''Comes from''' | |||
|'''Fault consequence''' | |||
|- | |||
|BNK0~2 | |||
|[[Memory card]] bank selection | |||
|Control | |||
|{{Chipname|NEO-D0}} | |||
|Errors on access to big memory cards | |||
|} | |||
=CPU ([[Z80]])= | |||
=Sound= | |||
*PAL: Palette RAM address decode for 68k access | |||
*PCK1B: Low 55ns, high 610 (1.5MHz) Clock to latch C ROM address from P0~P23 ([[NEO-273|mapping]]) on rising edge. | |||
*PCK2B: Low 55ns, high 610 (1.5MHz) Clock to latch S ROM address from P0~P15 ([[NEO-273|mapping]]) on rising edge. | |||
*SDA0~SDA15 : [[Z80]] address bus | *SDA0~SDA15 : [[Z80]] address bus | ||
*SDD0~SDD7: Z80 data bus | *SDD0~SDD7: Z80 data bus | ||
Line 35: | Line 262: | ||
*SYSTEM: low when onboard ROMs selected | *SYSTEM: low when onboard ROMs selected | ||
*SYSTEMB: inverted SYSTEM | *SYSTEMB: inverted SYSTEM | ||
[[Category:Chips]] | [[Category:Chips]] | ||
[[Category:Repairs]] |
Revision as of 04:46, 28 December 2018
Most names come from the official schematics.
Clocks
Name | Description | Type | Comes from | Fault consequence |
24M | 24MHz master clock | Clock | NEO-D0 | Nothing works, no video at all |
12M | 12MHz clock (24/2) non-inverted | Clock | NEO-D0 | Bad graphics |
8M | 8MHz clock (24/3) non-inverted | Clock | LSPC | No sound |
6MB | 6MHz clock (24/4) inverted | Clock | NEO-D0 | Black screen ? |
4M | 4MHz clock (24/6) non-inverted | Clock | LSPC | No sound |
4MB | 4MHz clock (24/6) inverted | Clock | LSPC + inverter | ? |
1MB | 3MHz (!) clock (24/8) inverted | Clock | NEO-D0 | ? |
68KCLK | 12MHz clock (24/2) non-inverted | Clock | NEO-D0 | Click of death |
68KCLKB | 12MHz clock (24/2) inverted | Clock | NEO-D0 | Bad ADPCM-B instruments in games using PCM |
CPU (68k)
Name | Description | Type | Comes from | Fault consequence |
A1~A23 | 68k address bus | Address | 68k | Click of death |
A22I,A23I | Altered address lines for 68k vector table swap | Address | NEO-E0 | Probably click of death |
/AS | 68k Address Strobe | Control | 68k | Probably click of death |
D0~D15 | 68k data bus | Data | Multiple | Click of death |
/DTACK | 68k Data Transmit ACKnowledge (see wait cycle) | Control | NEO-C1 | Click of death ? |
/PORTADRS | $200000-$2FFFFF (P2 ROM/Security chip) any access | Control | NEO-C1 | Game freezes, bad graphics |
/PORTOEL | $200000-$2FFFFF (P2 ROM/Security chip) odd byte read | Control | NEO-C1 | Game freezes, bad graphics |
/PORTOEU | $200000-$2FFFFF (P2 ROM/Security chip) even byte read | Control | NEO-C1 | Game freezes, bad graphics |
/PORTWEL | $200000-$2FFFFF (P2 ROM/Security chip) odd byte write | Control | NEO-C1 | Game freezes, multiplayer comm. error |
/PORTWEU | $200000-$2FFFFF (P2 ROM/Security chip) even byte write | Control | NEO-C1 | Game freezes, bad graphics |
/PWAIT0, /PWAIT1 | Delay configuration for P2 ROM reads, see wait cycle | Control | NEO-C1 | Game freezes (very likely) |
R/W | 68k Read/Write | Control | 68k | Click of death |
/ROMOE | $000000-$0FFFFF (P1 ROM) read | Control | NEO-C1 + AND | Game doesn't start |
/ROMOEL | $000000-$0FFFFF (P1 ROM) odd byte read | Control | NEO-C1 | Game doesn't start |
/ROMOEU | $000000-$0FFFFF (P1 ROM) even byte read | Control | NEO-C1 | Game doesn't start |
/ROMWAIT | Add 1-cycle delay for P1 ROM reads | Control | NEO-C1 | Game freezes (unlikely) |
/SROMOE | $C00000-$CFFFFF (System ROM) read | Control | NEO-E0 | Click of death |
/SROMOEL | $C00000-$CFFFFF (System ROM) odd byte read | Control | NEO-C1 | Click of death |
/SROMOEU | $C00000-$CFFFFF (System ROM) even byte read | Control | NEO-C1 | Click of death |
Graphics
Name | Description | Type | Comes from | Fault consequence |
2H1 | S ROM A3 | Address | LSPC | Bad fix graphics |
CA4 | C ROMs A4 | Address | LSPC | Bad sprite graphics |
C* or CR0~CR31 | C ROMs data bus (2*16bits), data for one 8-pixels line | Data | C ROM | Bad sprite graphics |
FIXD0~FIXD7 | Fix layer data bus, data for 2 pixels | Data | S ROM | Static vertical lines, solid color screen |
P0~P23 | Multiplexed P bus | Muxed | Multiple | Garbled or absent graphics |
PA0~PA11 | Palette RAM address bus | Address | NEO-B1 | Bad colors, snow, black screen |
Misc.
Name | Description | Type | Comes from | Fault consequence |
BNK0~2 | Memory card bank selection | Control | NEO-D0 | Errors on access to big memory cards |
CPU (Z80)
Sound
- PAL: Palette RAM address decode for 68k access
- PCK1B: Low 55ns, high 610 (1.5MHz) Clock to latch C ROM address from P0~P23 (mapping) on rising edge.
- PCK2B: Low 55ns, high 610 (1.5MHz) Clock to latch S ROM address from P0~P15 (mapping) on rising edge.
- SDA0~SDA15 : Z80 address bus
- SDD0~SDD7: Z80 data bus
- SDRAD0~SDRAD7: ADPCM-A ROM multiplexed bus (data/address)
- SDRA8,SDRA9,SDRA20~SDRA23: ADPCM-A ROM address bus
- SDPAD0~SDPAD7: ADPCM-B ROM multiplexed bus (data/address)
- SDPA8,SDPA9,SDPA10,SDPA11: ADPCM-B ROM address bus
- SYSTEM: low when onboard ROMs selected
- SYSTEMB: inverted SYSTEM