if PinCCLR=0 then ShiftReg=1FFFFh ;\done at falling CLK edge
PinSIN=ShiftRegBit0 ;/
;Mind that above is a software example - a hardware solution obviously
;wouldn't require CmpVal and XorVal registers - instead, hardware would
;directly deal with the PinAx (or NOT PinAx) signals.
Replacing or overwriting the EPROM in existing cartridges is easy, so the ACID doesn't prevent piracy or homebrew programming. However, it prevents commercial developers from producing unlicensed cartridges.