VIC-1210 3K RAM Cartridge
The VIC-1210 3K RAM Cartridge is a Random Access Memory expansion device produced by Commodore for the VIC-20 computer. It plugs into the cartridge port of the VIC-20 and thus provides a total of 6655 bytes free for user programs (including the VIC-20s built-in 3583 bytes of user RAM). The VIC-1210 is usually housed in a brown utility cartridge style case, although there are a few variations.
A 3K RAM expander such as the VIC-1210 will not cause the VIC-20 to move the location of video memory in the memory map (as occurs when 8K or larger expanders are attached). Therefore, most BASIC programs that run well on an unexpanded VIC-20 are also compatible with a 3K expanded VIC-20. The BASIC program area is changed so that it starts at location 1024 ($0400). With the cartridge plugged in, only on-board memory (4096-8191 or $1000-$1FFF) can be used as VIC screen and high resolution graphics areas.
By using a slot expander peripheral, the VIC-1210 can be used in combination with other RAM cartridges (such as the VIC-1110). However, an external RAM expansion in Block 1 ($2000-$3FFF) takes precedence over the 3K RAM in $0400-$0FFF. In that case, the screen RAM is moved down to $1000 and blocks the 3K RAM for BASIC.
The VIC-1210 uses the same PCB as the VIC-1211A Super Expander. By fitting a programmed 2532 EPROM, and a voltage stabilizing capacitor, the VIC-1210 can be upgraded to the VIC-1211A.
