64 banks available
switch is implemented again by use of high/low of VIA ORB PB6
switching is usually done by setting the corresponding DDR register to input (PB6 goes high automatically) or output (PB6 goes low automatically)
switch routine in general works this way:
first time when PB6 (external line from cartridge point of view) is set to high from low (after a LONG time... (>2000 cycles?) bank is resetted to 0
if another switch from high to low occurs within a short (but not too short) time (about 1500 cycles) bank is increased by one
so to reach "higher" banks we have to loop thru all lower banks...
the routine which does the bankswitching must not reside in flash memory, thus the actual switching routine must run in RAM-memory!
As long as not another PB6 using external device is emulated, VecFlash is detected automatically (this may change when EPROM RAM is implemented)