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Video Interface Chip
6560-101 4480 - On Board - VIC-1001.jpg
Developer: Commodore
Released: 1980-??-??
Type: Chip

1.) Square Wave
2.) Square Wave
3.) Square Wave
4.) Noise

The Video Interface Chip (VIC) is the defining chip of the Commodore VIC 20 series of 8-bit home computers. It handles graphics, movements of a plugged-in mouse, paddle or light gun, and audio.


On each of four channels, you can choose a pitch in 128 steps, down to roughly C♯1. Every channel is one octave higher than the other. The fourth channel is supposed to be noise, although it still sounds a bit melodic.

For all four channels together, you can only choose one volume, from 0 to 15. Changing the volume produces a click; the greater the change, the louder. This allows to play unsigned 4-bit PCM samples on a fifth channel. The VGMPF currently does not know if any game does that.



6560 from week 44 (autumn) 1980 on board of a VIC-1001.

Commodore's datasheet specifies to clock the 6560 at 14.31818 MHz for NTSC standard.

The 6560 divides its clock by 14 to determine the CPU clock, and further by 65×261 to determine the screen refresh rate.


Commodore's datasheet specifies to clock the 6561 at 4.436187 MHz (obviously a typo, where a 3 was omitted) for PAL standard.

The 6561 divides its clock by 4 to determine the CPU clock, and further by 71×312 to determine the screen refresh rate.


Release Device Chip
1980-??-?? VIC-1001 6560
1981-??-?? VIC 20 (NTSC) 6560
1981-??-?? VIC 20 (PAL) 6561
1981-??-?? VC-20 6561
1983-0?-?? VIC 21 6560


Several VIC 20 games play music and sound effects on the VIC.


Picture Gallery

Emulation Status

VICE 3.2 accurately emulates the VIC 20 (NTSC and PAL).