Programming the SID Sound Chip

The MOS 6581 SID (Sound Interface Device) is the most advanced sound chip in any home computer. Three voices, multiple waveforms, filters - its practically a synthesizer!

SID Memory Locations

Volume control: POKE 54296, volume (0-15)

Your First Sound

10 REM SIMPLE BEEP
20 POKE 54296,15     : REM MAX VOLUME
30 POKE 54277,9      : REM ATTACK/DECAY
40 POKE 54278,0      : REM SUSTAIN/RELEASE
50 POKE 54273,28     : REM FREQUENCY HI
60 POKE 54272,49     : REM FREQUENCY LO
70 POKE 54276,17     : REM TRIANGLE WAVE, GATE ON
80 FOR T=1 TO 500:NEXT: REM WAIT
90 POKE 54276,16     : REM GATE OFF

Play a Scale

10 POKE 54296,15:POKE 54277,0:POKE 54278,240
20 DATA 17,37,19,63,21,154,22,227
30 DATA 25,30,28,49,31,165,33,135
40 FOR N=1 TO 8
50 READ HI,LO
60 POKE 54273,HI:POKE 54272,LO
70 POKE 54276,33:FOR D=1 TO 200:NEXT
80 POKE 54276,32
90 NEXT N

Waveform Values

• 17 = Triangle (smooth, flute-like)
• 33 = Sawtooth (bright, brassy)
• 65 = Pulse (hollow, variable)
• 129 = Noise (drums, explosions)

"The SID chip brings arcade-quality sound into your home. Composers like Rob Hubbard and Martin Galway have created music that rivals professional studios!" - RUN Magazine