I/O Map
Expansion Region 1
1F000000h 80000h Expansion Region (default 512 Kbytes, max 8 MBytes)
1F000000h 100h Expansion ROM Header (IDs and Entrypoints)
Scratchpad
1F800000h 400h Scratchpad (1K Fast RAM) (Data Cache mapped to fixed address)
Memory Control 1
1F801000h 4 Expansion 1 Base Address (usually 1F000000h)
1F801004h 4 Expansion 2 Base Address (usually 1F802000h)
1F801008h 4 Expansion 1 Delay/Size (usually 0013243Fh; 512Kbytes 8bit-bus)
1F80100Ch 4 Expansion 3 Delay/Size (usually 00003022h; 1 byte)
1F801010h 4 BIOS ROM Delay/Size (usually 0013243Fh; 512Kbytes 8bit-bus)
1F801014h 4 SPU_DELAY Delay/Size (usually 200931E1h)
1F801018h 4 CDROM_DELAY Delay/Size (usually 00020843h or 00020943h)
1F80101Ch 4 Expansion 2 Delay/Size (usually 00070777h; 128-bytes 8bit-bus)
1F801020h 4 COM_DELAY / COMMON_DELAY (00031125h or 0000132Ch or 00001325h)
Peripheral I/O Ports
1F801040h 1/4 JOY_DATA Joypad/Memory Card Data (R/W)
1F801044h 4 JOY_STAT Joypad/Memory Card Status (R)
1F801048h 2 JOY_MODE Joypad/Memory Card Mode (R/W)
1F80104Ah 2 JOY_CTRL Joypad/Memory Card Control (R/W)
1F80104Eh 2 JOY_BAUD Joypad/Memory Card Baudrate (R/W)
1F801050h 1/4 SIO_DATA Serial Port Data (R/W)
1F801054h 4 SIO_STAT Serial Port Status (R)
1F801058h 2 SIO_MODE Serial Port Mode (R/W)
1F80105Ah 2 SIO_CTRL Serial Port Control (R/W)
1F80105Ch 2 SIO_MISC Serial Port Internal Register (R/W)
1F80105Eh 2 SIO_BAUD Serial Port Baudrate (R/W)
Memory Control 2
1F801060h 4/2 RAM_SIZE (usually 00000B88h; 2MB RAM mirrored in first 8MB)
Interrupt Control
1F801070h 2 I_STAT - Interrupt status register
1F801074h 2 I_MASK - Interrupt mask register
DMA Registers
1F80108xh DMA0 channel 0 - MDECin
1F80109xh DMA1 channel 1 - MDECout
1F8010Axh DMA2 channel 2 - GPU (lists + image data)
1F8010Bxh DMA3 channel 3 - CDROM
1F8010Cxh DMA4 channel 4 - SPU
1F8010Dxh DMA5 channel 5 - PIO (Expansion Port)
1F8010Exh DMA6 channel 6 - OTC (reverse clear OT) (GPU related)
1F8010F0h DPCR - DMA Control register
1F8010F4h DICR - DMA Interrupt register
1F8010F8h unknown
1F8010FCh unknown
Timers (aka Root counters)
1F80110xh Timer 0 Dotclock
1F80111xh Timer 1 Horizontal Retrace
1F80112xh Timer 2 1/8 system clock
CDROM Registers (Address.Read/Write.Index)
1F801800h.x.x 1 CD Index/Status Register (Bit0-1 R/W, Bit2-7 Read Only)
1F801801h.R.x 1 CD Response Fifo (R) (usually with Index1)
1F801802h.R.x 1/2 CD Data Fifo - 8bit/16bit (R) (usually with Index0..1)
1F801803h.R.0 1 CD Interrupt Enable Register (R)
1F801803h.R.1 1 CD Interrupt Flag Register (R/W)
1F801803h.R.2 1 CD Interrupt Enable Register (R) (Mirror)
1F801803h.R.3 1 CD Interrupt Flag Register (R/W) (Mirror)
1F801801h.W.0 1 CD Command Register (W)
1F801802h.W.0 1 CD Parameter Fifo (W)
1F801803h.W.0 1 CD Request Register (W)
1F801801h.W.1 1 Unknown/unused
1F801802h.W.1 1 CD Interrupt Enable Register (W)
1F801803h.W.1 1 CD Interrupt Flag Register (R/W)
1F801801h.W.2 1 Unknown/unused
1F801802h.W.2 1 CD Audio Volume for Left-CD-Out to Left-SPU-Input (W)
1F801803h.W.2 1 CD Audio Volume for Left-CD-Out to Right-SPU-Input (W)
1F801801h.W.3 1 CD Audio Volume for Right-CD-Out to Right-SPU-Input (W)
1F801802h.W.3 1 CD Audio Volume for Right-CD-Out to Left-SPU-Input (W)
1F801803h.W.3 1 CD Audio Volume Apply Changes (by writing bit5=1)
GPU Registers
1F801810h.Write 4 GP0 Send GP0 Commands/Packets (Rendering and VRAM Access)
1F801814h.Write 4 GP1 Send GP1 Commands (Display Control)
1F801810h.Read 4 GPUREAD Read responses to GP0(C0h) and GP1(10h) commands
1F801814h.Read 4 GPUSTAT Read GPU Status Register
MDEC Registers
1F801820h.Write 4 MDEC Command/Parameter Register (W)
1F801820h.Read 4 MDEC Data/Response Register (R)
1F801824h.Write 4 MDEC Control/Reset Register (W)
1F801824h.Read 4 MDEC Status Register (R)
SPU Voice 0..23 Registers
1F801C00h+N*10h 4 Voice 0..23 Volume Left/Right
1F801C04h+N*10h 2 Voice 0..23 ADPCM Sample Rate
1F801C06h+N*10h 2 Voice 0..23 ADPCM Start Address
1F801C08h+N*10h 4 Voice 0..23 ADSR Attack/Decay/Sustain/Release
1F801C0Ch+N*10h 2 Voice 0..23 ADSR Current Volume
1F801C0Eh+N*10h 2 Voice 0..23 ADPCM Repeat Address
SPU Control Registers
1F801D80h 4 Main Volume Left/Right
1F801D84h 4 Reverb Output Volume Left/Right
1F801D88h 4 Voice 0..23 Key ON (Start Attack/Decay/Sustain) (W)
1F801D8Ch 4 Voice 0..23 Key OFF (Start Release) (W)
1F801D90h 4 Voice 0..23 Channel FM (pitch lfo) mode (R/W)
1F801D94h 4 Voice 0..23 Channel Noise mode (R/W)
1F801D98h 4 Voice 0..23 Channel Reverb mode (R/W)
1F801D9Ch 4 Voice 0..23 Channel ON/OFF (status) (R)
1F801DA0h 2 Unknown? (R) or (W)
1F801DA2h 2 Sound RAM Reverb Work Area Start Address
1F801DA4h 2 Sound RAM IRQ Address
1F801DA6h 2 Sound RAM Data Transfer Address
1F801DA8h 2 Sound RAM Data Transfer Fifo
1F801DAAh 2 SPU Control Register (SPUCNT)
1F801DACh 2 Sound RAM Data Transfer Control
1F801DAEh 2 SPU Status Register (SPUSTAT) (R)
1F801DB0h 4 CD Volume Left/Right
1F801DB4h 4 Extern Volume Left/Right
1F801DB8h 4 Current Main Volume Left/Right
1F801DBCh 4 Unknown? (R/W)
SPU Reverb Configuration Area
1F801DC0h 2 dAPF1 Reverb APF Offset 1
1F801DC2h 2 dAPF2 Reverb APF Offset 2
1F801DC4h 2 vIIR Reverb Reflection Volume 1
1F801DC6h 2 vCOMB1 Reverb Comb Volume 1
1F801DC8h 2 vCOMB2 Reverb Comb Volume 2
1F801DCAh 2 vCOMB3 Reverb Comb Volume 3
1F801DCCh 2 vCOMB4 Reverb Comb Volume 4
1F801DCEh 2 vWALL Reverb Reflection Volume 2
1F801DD0h 2 vAPF1 Reverb APF Volume 1
1F801DD2h 2 vAPF2 Reverb APF Volume 2
1F801DD4h 4 mSAME Reverb Same Side Reflection Address 1 Left/Right
1F801DD8h 4 mCOMB1 Reverb Comb Address 1 Left/Right
1F801DDCh 4 mCOMB2 Reverb Comb Address 2 Left/Right
1F801DE0h 4 dSAME Reverb Same Side Reflection Address 2 Left/Right
1F801DE4h 4 mDIFF Reverb Different Side Reflection Address 1 Left/Right
1F801DE8h 4 mCOMB3 Reverb Comb Address 3 Left/Right
1F801DECh 4 mCOMB4 Reverb Comb Address 4 Left/Right
1F801DF0h 4 dDIFF Reverb Different Side Reflection Address 2 Left/Right
1F801DF4h 4 mAPF1 Reverb APF Address 1 Left/Right
1F801DF8h 4 mAPF2 Reverb APF Address 2 Left/Right
1F801DFCh 4 vIN Reverb Input Volume Left/Right
SPU Internal Registers
1F801E00h+N*04h 4 Voice 0..23 Current Volume Left/Right
1F801E60h 20h Unknown? (R/W)
1F801E80h 180h Unknown? (Read: FFh-filled) (Unused or Write only?)
Expansion Region 2 (default 128 bytes, max 8 KBytes)
1F802000h 80h Expansion Region (8bit data bus, crashes on 16bit access?)
Expansion Region 2 - Dual Serial Port (for TTY Debug Terminal)
1F802020h/1st DUART Mode Register 1.A (R/W)
1F802020h/2nd DUART Mode Register 2.A (R/W)
1F802021h/Read DUART Status Register A (R)
1F802021h/Write DUART Clock Select Register A (W)
1F802022h/Read DUART Toggle Baud Rate Generator Test Mode (Read=Strobe)
1F802022h/Write DUART Command Register A (W)
1F802023h/Read DUART Rx Holding Register A (FIFO) (R)
1F802023h/Write DUART Tx Holding Register A (W)
1F802024h/Read DUART Input Port Change Register (R)
1F802024h/Write DUART Aux. Control Register (W)
1F802025h/Read DUART Interrupt Status Register (R)
1F802025h/Write DUART Interrupt Mask Register (W)
1F802026h/Read DUART Counter/Timer Current Value, Upper/Bit15-8 (R)
1F802026h/Write DUART Counter/Timer Reload Value, Upper/Bit15-8 (W)
1F802027h/Read DUART Counter/Timer Current Value, Lower/Bit7-0 (R)
1F802027h/Write DUART Counter/Timer Reload Value, Lower/Bit7-0 (W)
1F802028h/1st DUART Mode Register 1.B (R/W)
1F802028h/2nd DUART Mode Register 2.B (R/W)
1F802029h/Read DUART Status Register B (R)
1F802029h/Write DUART Clock Select Register B (W)
1F80202Ah/Read DUART Toggle 1X/16X Test Mode (Read=Strobe)
1F80202Ah/Write DUART Command Register B (W)
1F80202Bh/Read DUART Rx Holding Register B (FIFO) (R)
1F80202Bh/Write DUART Tx Holding Register B (W)
1F80202Ch/None DUART Reserved Register (neither R nor W)
1F80202Dh/Read DUART Input Port (R)
1F80202Dh/Write DUART Output Port Configuration Register (W)
1F80202Eh/Read DUART Start Counter Command (Read=Strobe)
1F80202Eh/Write DUART Set Output Port Bits Command (Set means Out=LOW)
1F80202Fh/Read DUART Stop Counter Command (Read=Strobe)
1F80202Fh/Write DUART Reset Output Port Bits Command (Reset means Out=HIGH)
Expansion Region 2 - Int/Dip/Post
1F802000h 1 DTL-H2000: ATCONS STAT (R)
1F802002h 1 DTL-H2000: ATCONS DATA (R and W)
1F802004h 2 DTL-H2000: Whatever 16bit data ?
1F802030h 1/4 DTL-H2000: Secondary IRQ10 Flags
1F802032h 1 DTL-H2000: Whatever IRQ Control ?
1F802040h 1 DTL-H2000: Bootmode "Dip switches" (R)
1F802041h 1 PSX: POST (external 7 segment display, indicate BIOS boot status)
1F802042h 1 DTL-H2000: POST/LED (similar to POST) (other addr, 2-digit wide)
1F802070h 1 PS2: POST2 (similar to POST, but PS2 BIOS uses this address)
Expansion Region 2 - Nocash Emulation Expansion
1F802060h Emu-Expansion ID1 "E" (R)
1F802061h Emu-Expansion ID2 "X" (R)
1F802062h Emu-Expansion ID3 "P" (R)
1F802063h Emu-Expansion Version (01h) (R)
1F802064h Emu-Expansion Enable1 "O" (R/W)
1F802065h Emu-Expansion Enable2 "N" (R/W)
1F802066h Emu-Expansion Halt (R)
1F802067h Emu-Expansion Turbo Mode Flags (R/W)
Expansion Region 2 - PCSX-Redux Emulation Expansion
1F802080h 4 Redux-Expansion ID "PCSX" (R)
1F802080h 1 Redux-Expansion Console putchar (W)
1F802081h 1 Redux-Expansion Debug break (W)
1F802082h 1 Redux-Expansion Exit code (W)
1F802084h 4 Redux-Expansion Notification message pointer (W)
Expansion Region 3 (default 1 byte, max 2 MBytes)
1FA00000h - Not used by BIOS or any PSX games
1FA00000h - POST3 (similar to POST, but PS2 BIOS uses this address)
BIOS Region (default 512 Kbytes, max 4 MBytes)
1FC00000h 80000h BIOS ROM (512Kbytes) (Reset Entrypoint at BFC00000h)
Memory Control 3 (Cache Control)
FFFE0130h 4 Cache Control
Coprocessor Registers
COP0 System Control Coprocessor - 32 registers (not all used)
COP1 N/A
COP2 Geometry Transformation Engine (GTE) - 64 registers (most are used)
COP3 N/A