Instructions for the EPROM-expansion

The EPROM-expansion is controlled by a register at adress $fd17 (64791). The bits have the following function:

Bit 0-3  Select one from max. 16 different areas of the expansion. It
         depends from your expansion-size, how much areas you have. If you
         have a smaller expansion the areas are mirrored and only some bits
         are used. (96kb=no bit; 192kb=Bit 0; 384kb=Bit 0/1; 768kb=Bit 0-2;
         1,5MB=Bit 0-3)
         Standard is all bits set to "1". Use for your programs the highest
         area in your expansion as first.
Bit 7    1: external EPROMs (bank a, f on expansion-port) disabled
         0: external EPROMs (bank a, f on expansion-port) enabled, intern
         bank a, f disabled

The other bits are used in the sRAM-expansion only.