Posted By
SVS
on 2015-02-18
13:48:59
 |  Re: Bankswitching of Plussy and its programming
To turn off the ROM reading, just write into $FF3F location (any value, even zero). The following read operations (for ex. LDA) do read from RAM.
To return reading from ROM just write (any value) into $FF3E.
Of course if the nterrupt is active you have to avoid an IRQ call while the RAM reading is on. Since the IRQ routine resides into ROM it would cause a crash. Then when reading is set from RAM the interrupt has to be disabled.
Example:
SEI
STA $FF3F
.... reading operations from RAM
STA $FF3E
CLI
And now a question @icbrkr: what compiler are you using?
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