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blondie7575/AVRInterruptHandler.as

Created August 19, 2012 23:59
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AVRInterruptHandler.as
INT2_vect:
// Get ourselves completely off the bus
clr accum
out PORTD,accum
out DDRD,accum
out DDRC,accum
out DDRA,accum
sbi PORTB,vramWrite
sbi PORTB,vramOE
// Enable the CPU's bus access
cbi PORTB,cpuBusAllow
// Assuming CPU is now driving the bus,
// perform the write
cbi PORTB,vramWrite
sbi PORTB,vramWrite
// Cut off the CPU and reenable our access
sbi PORTB,cpuBusAllow
cbi PORTB,vramOE
ldi accum,0xff
out DDRC,accum
out DDRA,accum
reti
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