- f1 - 0K, unexpanded VIC20
- f3 - 3K, 3K RAM in block 0
- f5 - 8K, 8K RAM in block 1
- f7 - 35K, 3K RAM in block 0, 4x8K RAM in blocks 1,2,3 and 5
The shifted function keys give a further four RAM configurations
- f2 - 16K, 2x8K RAM in blocks 1 and 2
- f4 - 24K, 3x8K RAM in blocks 1, 2 and 3
- f6 - 27K, 3K RAM in block 0, 3x8K RAM in blocks 1,2 and 3
- f8 - 32K, 4x8K RAM in blocks 1,2,3 and 5
Once the RAM is selected, the VIC20 will be booted and will continue with the amount of RAM selected until the power is removed. As ever, BASIC does not count all the RAM, so the maximum you should ever see is 28159 bytes free, but the RAM in block 5 (and block 0 when there is RAM elsewhere) can be used for assembler programs or ROM images etc.
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