Description for CS/A CPUEMU, version 1.0
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whatsit : 6502 Emulation board
I/O     : --
Mem     : 64k memory of the simulated 6502 at $2****

This boards allows to replace a 6502 CPU in another computer
with a cable to this board. The 64k memory of the emulated 6502 
are mapped to $2**** in the CS/A65 memory.

All Data and Address lines are buffered. When a write takes place
outside the mapped memory ($2****) the data bus driver is disabled,
and the simulated R/-W line signals a read, not write.

Warning: this design has a serious flaw: When an address outside the
mapped memory is accessed, a read is done in the simulated system
with the lower 16 address bits of the CS/A65 address as 6502 address.
If by accident this address is something like a clear-on-read this
register is accessed, cleared, and might change the state of the
system!
Instead a fixed, save address should be used, but this is not implemented.