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| HEX | DECIMAL | BITS | DESCRIPTION |
|---|---|---|---|
| 0000 | 0 | 7-0 | MOS 6510 Data Direction
Register (xx101111) Bit= 1: Output, Bit=0: Input, x=Don't Care |
| 0001 | 1 | MOS 6510 Micro-Processor On-Chip I/O Port | |
| 0 | /LORAM Signal (0=Switch BASIC ROM Out) | ||
| 1 | /HIRAM Signal (0=Switch Kernal ROM Out) | ||
| 2 | /CHAREN Signal (0=Switch Char. ROM In) | ||
| 3 | Cassette Data Output Line | ||
| 4 | Cassette Switch Sense: 1 = Switch Closed | ||
| 5 | Cassette Motor Control 0 = ON, 1 = OFF | ||
| 6-7 | Undefined | ||
| D000-D02E | 53248-54271 | MOS 6566 VIDEO INTERFACE CONTROLLER (VIC) | |
| D000 | 53248 | Sprite 0 X Pos | |
| D001 | 53249 | Sprite 0 Y Pos | |
| D002 | 53250 | Sprite 1 X Pos | |
| D003 | 53251 | Sprite 1 Y Pos | |
| D004 | 53252 | Sprite 2 X Pos | |
| D005 | 53253 | Sprite 2 Y Pos | |
| D006 | 53254 | Sprite 3 X Pos | |
| D007 | 53255 | Sprite 3 Y Pos | |
| D008 | 53256 | Sprite 4 X Pos | |
| D009 | 53257 | Sprite 4 Y Pos | |
| D00A | 53258 | Sprite 5 X Pos | |
| D00B | 53259 | Sprite 5 Y Pos | |
| D00C | 53260 | Sprite 6 X Pos | |
| D00D | 53261 | Sprite 6 Y Pos | |
| D00E | 53262 | Sprite 7 X Pos | |
| D00F | 53263 | Sprite 7 Y Pos | |
| D010 | 53264 | Sprites 0-7 X Pos (msb of X coord.) | |
| D011 | 53265 | VIC Control Register | |
| 7 | Raster Compare: (Bit 8) See 53266 | ||
| 6 | Extended Color Text Mode: 1 = Enable | ||
| 5 | Bit Map Mode: 1 = Enable | ||
| 4 | Blank Screen to Border Color: 0 = Blank | ||
| 3 | Select 24/25 Row Text Display: 1=25 Rows | ||
| 2-0 | Smooth Scroll to Y Dot-Position (0-7) | ||
| D012 | 53266 | Read Raster/Write Raster Value for Compare IRQ | |
| D013 | 53267 | Light-Pen Latch X Pos | |
| D014 | 53268 | Light-Pen Latch Y Pos | |
| D015 | 53269 | Sprite display Enable: 1 = Enable | |
| D016 | 53270 | VIC Control Register | |
| 7-6 | Unused | ||
| 5 | ALWAYS SET THIS BIT TO 0 ! | ||
| 4 | Multi-Color Mode: 1 = Enable (Text or Bit-Map) | ||
| 3 | Select 38/40 Column Text Display: 1 = 40 Cols | ||
| 2-0 | Smooth Scroll to X Pos | ||
| D017 | 53271 | Sprites 0-7 Expand 2x Vertical (Y) | |
| D018 | 53272 | VIC Memory Control Register | |
| 7-4 | Video Matrix Base Address (inside VIC) | ||
| 3-1 | Character Dot-Data Base Address (inside VIC) | ||
| 0 | Select upper/lower Character Set | ||
| D019 | 53273 | VIC Interrupt Flag Register (Bit = 1: IRQ Occurred) | |
| 7 | Set on Any Enabled VIC IRQ Condition | ||
| 3 | Light-Pen Triggered IRQ Flag | ||
| 2 | Sprite to Sprite Collision IRQ Flag | ||
| 1 | Sprite to Background Collision IRQ Flag | ||
| 0 | Raster Compare IRQ Flag | ||
| D01A | 53274 | IRQ Mask Register: 1 = Interrupt Enabled | |
| D01B | 53275 | Sprite to Background Display Priority: 1 = Sprite | |
| D01C | 53276 | Sprites 0-7 Multi-Color Mode Select: 1 = M.C.M. | |
| D01D | 53277 | Sprites 0-7 Expand 2x Horizontal (X) | |
| D01E | 53278 | Sprite to Sprite Collision Detect | |
| D01F | 53279 | Sprite to Background Collision Detect | |
| D020 | 53280 | Border Color | |
| D021 | 53281 | Background Color 0 | |
| D022 | 53282 | Background Color 1 | |
| D023 | 53283 | Background Color 2 | |
| D024 | 53284 | Background Color 3 | |
| D025 | 53285 | Sprite Multi-Color Register 0 | |
| D026 | 53286 | Sprite Multi-Color Register 1 | |
| D027 | 53287 | Sprite 0 Color | |
| D028 | 53288 | Sprite 1 Color | |
| D029 | 53289 | Sprite 2 Color | |
| D02A | 53290 | Sprite 3 Color | |
| D02B | 53291 | Sprite 4 Color | |
| D02C | 53292 | Sprite 5 Color | |
| D02D | 53293 | Sprite 6 Color | |
| D02E | 53294 | Sprite 7 Color | |
| D400-D7FF | 54272-55295 | MOS 6581 SOUND INTERFACE DEVICE (SID) | |
| D400 | 54272 | Voice 1: Frequency Control - Low-Byte | |
| D401 | 54273 | Voice 1: Frequency Control - High-Byte | |
| D402 | 54274 | Voice 1: Pulse Waveform Width - Low-Byte | |
| D403 | 54275 | 7-4 | Unused |
| 3-0 | Voice 1: Pulse Waveform Width - High-Nybble | ||
| D404 | 54276 | Voice 1: Control Register | |
| 7 | Select Random Noise Waveform, 1 = On | ||
| 6 | Select Pulse Waveform, 1 = On | ||
| 5 | Select Sawtooth Waveform, 1 = On | ||
| 4 | Select Triangle Waveform, 1 = On | ||
| 3 | Test Bit: 1 = Disable Oscillator 1 | ||
| 2 | Ring Modulate Osc. 1 with Osc. 3 Output, 1 = On | ||
| 1 | Synchronize Osc.1 with Osc.3 Frequency, 1 = On | ||
| 0 | Gate Bit: 1 = Start Att/Dec/Sus, 0 = Start Release | ||
| D405 | 54277 | Envelope Generator 1: Attack/Decay Cycle Control | |
| 7-4 | Select Attack Cycle Duration: 0-15 | ||
| 3-0 | Select Decay Cycle Duration: 0-15 | ||
| D406 | 54278 | Envelope Generator 1: Sustain/Release Cycle Control | |
| 7-4 | Select Sustain Cycle Duration: 0-15 | ||
| 3-0 | Select Release Cycle Duration: 0-15 | ||
| D407 | 54279 | Voice 2: Frequency Control - Low-Byte | |
| D408 | 54280 | Voice 2: Frequency Control - High-Byte | |
| D409 | 54281 | Voice 2: Pulse Waveform Width - Low-Byte | |
| D40A | 54282 | 7-4 | Unused |
| 3-0 | Voice 2: Pulse Waveform Width - High-Nybble | ||
| D40B | 54283 | Voice 2: Control Register | |
| 7 | Select Random Noise Waveform, 1 = On | ||
| 6 | Select Pulse Waveform, 1 = On | ||
| 5 | Select Sawtooth Waveform, 1 = On | ||
| 4 | Select Triangle Waveform, 1 = On | ||
| 3 | Test Bit: 1 = Disable Oscillator 1 | ||
| 2 | Ring Modulate Osc. 2 with Osc. 1 Output, 1 = On | ||
| 1 | Synchronize Osc.2 with Osc. 1 Frequency, 1 = On | ||
| 0 | Gate Bit: 1 = Start Att/Dec/Sus, 0 = Start Release | ||
| D40C | 54284 | Envelope Generator 2: Attack / Decay Cycle Control | |
| 7-4 | Select Attack Cycle Duration: 0-15 | ||
| 3-0 | Select Decay Cycle Duration: 0-15 | ||
| D40D | 54285 | Envelope Generator 2: Sustain / Release Cycle Control | |
| 7-4 | Select Sustain Cycle Duration: 0-15 | ||
| 3-0 | Select Release Cycle Duration: 0-15 | ||
| D40E | 54286 | Voice 3: Frequency Control - Low-Byte | |
| D40F | 54287 | Voice 3: Frequency Control - High-Byte | |
| D410 | 54288 | Voice 3: Pulse Waveform Width - Low-Byte | |
| D411 | 54289 | 7-4 | Unused |
| 3-0 | Voice 3: Pulse Waveform Width - High-Nybble | ||
| D412 | 54290 | Voice 3: Control Register | |
| 7 | Select Random Noise Waveform, 1 = On | ||
| 6 | Select Pulse Waveform, 1 = On | ||
| 5 | Select Sawtooth Waveform, 1 = On | ||
| 4 | Select Triangle Waveform, 1 = On | ||
| 3 | Test Bit: 1 = Disable Oscillator 1 | ||
| 2 | Ring Modulate Osc. 3 with Osc. 2 Output, 1 = On | ||
| 1 | Synchronize Osc. 3 with Osc.2 Frequency, 1 = On | ||
| 0 | Gate Bit: 1 = Start Att/Dec/Sus, 0 = Start Release | ||
| D413 | 54291 | Envelope Generator 3: Attack/Decay Cycle Control | |
| 7-4 | Select Attack Cycle Duration: 0-15 | ||
| 3-0 | Select Decay Cycle Duration: 0-15 | ||
| D414 | 54285 | Envelope Generator 3: Sustain / Release Cycle Control | |
| 7-4 | Select Sustain Cycle Duration: 0-15 | ||
| 3-0 | Select Release Cycle Duration: 0-15 | ||
| D415 | 54293 | Filter Cutoff Frequency: Low-Nybble (Bits 2-0) | |
| D416 | 54294 | Filter Cutoff Frequency: High-Byte | |
| D417 | 54295 | Filter Resonance Control / Voice Input Control | |
| 7-4 | Select Filter Resonance: 0-15 | ||
| 3 | Filter External Input: 1 = Yes, 0 = No | ||
| 2 | Filter Voice 3 Output: 1 = Yes, 0 = No | ||
| 1 | Filter Voice 2 Output: 1 = Yes, 0 = No | ||
| 0 | Filter Voice 1 Output: 1 = Yes, 0 = No | ||
| D418 | 54296 | Select Filter Mode and Volume | |
| 7 | Cut-Off Voice 3 Output: 1 = Off, 0 = On | ||
| 6 | Select Filter High-Pass Mode: 1 = On | ||
| 5 | Select Filter Band-Pass Mode: 1 = On | ||
| 4 | Select Filter Low-Pass Mode: 1 = On | ||
| 3-0 | Select Output Volume: 0-15 | ||
| D419 | 54297 | Analog/Digital Converter: Game Paddle 1 (0-255) | |
| D41A | 54298 | Analog/Digital Converter: Game Paddle 2 (0-255) | |
| D41B | 54299 | Oscillator 3 Random Number Generator | |
| D41C | 54230 | Envelope Generator 3 Output | |
| D500-D7FF | 54528-55295 | SID IMAGES | |
| D800-DBFF | 55296-56319 | Color RAM (Nybbles) | |
| DC00-DCFF | 56320-56575 | MOS 6526 Complex Interface Adapter (CIA) #1 | |
| DC00 | 56320 | Data Port A (Keyboard, Joystick, Paddles, Light-Pen) | |
| 7-0 | Write Keyboard Column Values for Keyboard Scan | ||
| 7-6 | Read Paddles on Port A / B (01 = Port A, 10 = Port B) | ||
| 4 | Joystick A Fire Button: 1 = Fire | ||
| 3-2 | Paddle Fire Buttons | ||
| 3-0 | Joystick A Direction (0-15) | ||
| DC01 | 56321 | Data Port B (Keyboard, Joystick, Paddles): Game Port 1 | |
| 7-0 | Read Keyboard Row Values for Keyboard Scan | ||
| 7 | Timer B Toggle/Pulse Output | ||
| 6 | Timer A: Toggle/Pulse Output | ||
| 4 | Joystick 1 Fire Button: 1 = Fire | ||
| 3-2 | Paddle Fire Buttons | ||
| 3-0 | Joystick 1 Direction | ||
| DC02 | 56322 | Data Direction Register - Port A (56320) | |
| DC03 | 56323 | Data Direction Register - Port B (56321) | |
| DC04 | 56324 | Timer A: Low-Byte | |
| DC05 | 56325 | Timer A: High-Byte | |
| DC06 | 56326 | Timer B: Low-Byte | |
| DC07 | 56327 | Timer B: High-Byte | |
| DC08 | 56328 | Time-of-Day Clock: 1/10 Seconds | |
| DC09 | 56329 | Time-of-Day Clock: Seconds | |
| DC0A | 56330 | Time-of-Day Clock: Minutes | |
| DC0B | 56331 | Time-of-Day Clock: Hours + AM/PM Flag (Bit 7) | |
| DC0C | 56332 | Synchronous Serial I/O Data Buffer | |
| DC0D | 56333 | CIA Interrupt Control Register (Read IRQs/Write Mask) | |
| 7 | IRQ Flag (1 = IRQ Occurred) / Set-Clear Flag | ||
| 4 | FLAG1 IRQ (Cassette Read / Serial Bus SRQ Input) | ||
| 3 | Serial Port Interrupt | ||
| 2 | Time-of-Day Clock Alarm Interrupt | ||
| 1 | Timer B Interrupt | ||
| 0 | Timer A Interrupt | ||
| DC0E | 56334 | CIA Control Register A | |
| 7 | Time-of-Day Clock Frequency: 1 = 50 Hz, 0 = 60 Hz | ||
| 6 | Serial Port I/O Mode Output, 0 = Input | ||
| 5 | Timer A Counts: 1 = CNT Signals, 0 = System 02 Clock | ||
| 4 | Force Load Timer A: 1 = Yes | ||
| 3 | Timer A Run Mode: 1 = One-Shot, 0 = Continuous | ||
| 2 | Timer A Output Mode to PB6: 1 = Toggle, 0 = Pulse | ||
| 1 | Timer A Output on PB6: 1 = Yes, 0 = No | ||
| 0 | Start/Stop Timer A: 1 = Start, 0 = Stop | ||
| DC0F | 56335 | CIA Control Register B | |
| 7 | Set Alarm/TOD-Clock: 1 = Alarm, 0 = Clock | ||
| 6-5 | Timer B Mode Select: 00 = Count System 02 Clock Pulses 01 = Count Positive CNT Transitions 10 = Count Timer A Underflow Pulses 11 = Count Timer A Underflows While CNT Positive | ||
| 4-0 | Same as CIA Control Reg. A - for Timer B | ||
| DD00-DDFF | 56576-56831 | MOS 6526 Complex Interface Adapter (CIA) #2 | |
| DD00 | 56576 | Data Port A (Serial Bus, RS-232, VIC Memory Control) | |
| 7 | Serial Bus Data Input | ||
| 6 | Serial Bus Clock Pulse Input | ||
| 5 | Serial Bus Data Output | ||
| 4 | Serial Bus Clock Pulse Output | ||
| 3 | Serial Bus ATN Signal Output | ||
| 2 | RS-232 Data Output (User Port) | ||
| 1-0 | VIC Chip System Memory Bank Select (Default = 11) | ||
| DD01 | 56577 | Data Port B (User Port, RS-232) | |
| 7 | User / RS-232 Data Set Ready | ||
| 6 | User / RS-232 Clear to Send | ||
| 5 | User | ||
| 4 | User / RS-232 Carrier Detect | ||
| 3 | User / RS-232 Ring Indicator | ||
| 2 | User / RS-232 Data Terminal Ready | ||
| 1 | User / RS-232 Request to Send | ||
| 0 | User / RS-232 Received Data | ||
| DD02 | 56578 | Data Direction Register - Port A | |
| DD03 | 56579 | Data Direction Register - Port B | |
| DD04 | 56580 | Timer A: Low-Byte | |
| DD05 | 56581 | Timer A: High-Byte | |
| DD06 | 56582 | Timer B: Low-Byte | |
| DD07 | 56583 | Timer B: High-Byte | |
| DD08 | 56584 | Time-of-Day Clock: 1/10 Seconds | |
| DD09 | 56585 | Time-of-Day Clock: Seconds | |
| DD0A | 56586 | Time-of-Day Clock: Minutes | |
| DD0B | 56587 | Time-of-Day Clock: Hours + AM/PM Flag (Bit 7) | |
| DD0C | 56588 | Synchronous Serial I/O Data Buffer | |
| DD0D | 56589 | CIA Interrupt Control Register (Read NMls/Write Mask) | |
| 7 | NMI Flag (1 = NMI Occurred) / Set-Clear Flag | ||
| 4 | FLAG1 NMI (User/RS-232 Received Data Input) | ||
| 3 | Serial Port Interrupt | ||
| 1 | Timer B Interrupt | ||
| 0 | Timer A Interrupt | ||
| DD0E | 56590 | CIA Control Register A | |
| 7 | Time-of-Day Clock Frequency: 1 = 50 Hz, 0 = 60 Hz | ||
| 6 | Serial Port I/O Mode Output, 0 = Input | ||
| 5 | Timer A Counts: 1 = CNT Signals, 0 = System 02 Clock | ||
| 4 | Force Load Timer A: 1 = Yes | ||
| 3 | Timer A Run Mode: 1 = One-Shot, 0 = Continuous | ||
| 2 | Timer A Output Mode to PB6: 1 = Toggle, 0 = Pulse | ||
| 1 | Timer A Output on PB6: 1 = Yes, 0 = No | ||
| 0 | Start/Stop Timer A: 1 = Start, 0 = Stop | ||
| DD0F | 56591 | CIA Control Register B | |
| 7 | Set Alarm/TOD-Clock: 1 = Alarm, 0 = Clock | ||
| 6-5 | Timer B Mode Select: 00 = Count System 02 Clock Pulses 01 = Count Positive CNT Transitions 10 = Count Timer A Underflow Pulses 11 = Count Timer A Underflows While CNT Positive | ||
| 4-0 | Same as CIA Control Reg. A - for Timer B | ||
| DE00-DEFF | 56832-57087 | Reserved for Future I/O Expansion | |
| DF00-DFFF | 57088-57343 | Reserved for Future I/O Expansion |
| This page has been created by Sami Rautiainen. | |
| Read the small print. | Last updated January 10, 2003. |