| 1 | -6581- SID |
28 | ||||
| 2 | 27 | |||||
| 3 | 26 | |||||
| 4 | 25 | |||||
| 5 | 24 | |||||
| 6 | 23 | |||||
| 7 | 22 | |||||
| 8 | 21 | |||||
| 9 | 20 | |||||
| 10 | 19 | |||||
| 11 | 18 | |||||
| 12 | 17 | |||||
| 13 | 16 | |||||
| 14 | 15 |
. Offsets are in hex.
| Offset | Bit | Function | |
| 00 | Frequency Control - Low-Byte, High-Byte | Voice 1 | |
| 02 | Pulse Waveform Width - Low-Byte | ||
| 03 | 7-4 | Unused | |
| 3-0 | Pulse Waveform Width - High-Nybble | ||
| 04 | 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 | ||
| 05 | Envelope Generator 1: Attack / Decay Cycle Control | ||
| 7-4 | Select Attack Cycle Duration: 0-15 | ||
| 3-0 | Select Decay Cycle Duration: 0-15 | ||
| 06 | Envelope Generator 1: Sustain / Release Cycle Control | ||
| 7-4 | Select Sustain Cycle Duration: 0-15 | ||
| 3-0 | Select Release Cycle Duration: 0-15 | ||
| 07-0D | Same structure as Voice 1 | Voice 2 | |
| 0E-13 | Same structure as Voice 1 | Voice 3 | |
| 15 | Cutoff Frequency: Low-Nybble (Bits 2-0) | Filter | |
| 16 | Cutoff Frequency: High-Byte | ||
| 17 | Resonance Control / Voice Input Control | ||
| 7-4 | Select Filter Resonance: 0-15 | ||
| 3 | External Input: 1 = Yes, 0 = No | ||
| 2 | Voice 3 Output: 1 = Yes, 0 = No | ||
| 1 | Voice 2 Output: 1 = Yes, 0 = No | ||
| 0 | Voice 1 Output: 1 = Yes, 0 = No | ||
| 18 | Select Mode and Volume | ||
| 7 | Cut-Off Voice 3 Output: 1 = Off, 0 = On | ||
| 6 | Select High-Pass Mode: 1 = On | ||
| 5 | Select Band-Pass Mode: 1 = On | ||
| 4 | Select Low-Pass Mode: 1 = On | ||
| 3-0 | Select Output Volume: 0-15 | ||
| 19 | Analog/Digital Converter: Game Paddle 1 (0-255) | ||
| 1A | Analog/Digital Converter: Game Paddle 2 (0-255) | ||
| 1B | Oscillator 3 Random Number Generator | ||
| 1C | Envelope Generator 3 Output |