Signals: Difference between revisions

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(Added decode signals)
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|'''Comes from'''
|'''Comes from'''
|'''Fault consequence'''
|'''Fault consequence'''
|-
|/DIPRD0
|$300000~$31FFFF odd byte reads
|Control
|{{Chipname|NEO-C1}}
|Can't read [[hardware DIPs]], test button state and system type. See {{Reg|REG_DIPSW}} and {{Reg|REG_SYSTYPE}}.
|-
|/DIPRD1
|$320000~$33FFFF odd byte reads
|Control
|{{Chipname|NEO-C1}}
|Coins aren't detected, RTC access problems. See {{Reg|REG_STATUS_A}}.
|-
|/BITW0
|$380000~$39FFFF odd byte writes
|Control
|{{Chipname|NEO-C1}}
|No [[Pinouts#Joypad_ports|joypad]] output control, memory card access problems, MVS slot selection problems, erratic credits displays and marquee control, RTC access problems, no [[coin counter]]s and [[coin lockout]]s control. See [[Memory mapped registers]].
|-
|/BITW1
|$3A0000~$3BFFFF odd byte writes
|Control
|{{Chipname|NEO-C1}}
|Spurious or impossible writes to [[Memory_mapped_registers#System_registers|system registers]].
|-
|/BITWD0
|$3A0000~$3BFFFF odd byte writes
|Control
|{{Chipname|NEO-F0}}
|No [[Pinouts#Joypad_ports|joypad]] output control, memory card access problems. See {{Reg|REG_POUTPUT}} and {{Reg|REG_CRDBANK}}. Depends on /BITW0.
|-
|-
|BNK0~2
|BNK0~2
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|Control
|Control
|{{Chipname|NEO-D0}}
|{{Chipname|NEO-D0}}
|Errors on access to big memory cards
|Access problems with big memory cards.
|}
|}


Revision as of 01:47, 12 November 2019

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
/DIPRD0 $300000~$31FFFF odd byte reads Control NEO-C1 Can't read hardware DIPs, test button state and system type. See REG_DIPSW and REG_SYSTYPE.
/DIPRD1 $320000~$33FFFF odd byte reads Control NEO-C1 Coins aren't detected, RTC access problems. See REG_STATUS_A.
/BITW0 $380000~$39FFFF odd byte writes Control NEO-C1 No joypad output control, memory card access problems, MVS slot selection problems, erratic credits displays and marquee control, RTC access problems, no coin counters and coin lockouts control. See Memory mapped registers.
/BITW1 $3A0000~$3BFFFF odd byte writes Control NEO-C1 Spurious or impossible writes to system registers.
/BITWD0 $3A0000~$3BFFFF odd byte writes Control NEO-F0 No joypad output control, memory card access problems. See REG_POUTPUT and REG_CRDBANK. Depends on /BITW0.
BNK0~2 Memory card bank selection Control NEO-D0 Access problems with 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
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