|54018|$D302|PACTL|Port A Control|all

|7|PA7|read only: Interrupt status of PROCEED, 1=Interrupt
|6|PA6|always 0
|5|PA5|always 1
|4|PA4|always 1 
|3|PA3|Cassette player motor control, 0=on, 1=off
|2|PA2|1=use Port A for data input/output, 0=define data direction, see below 
|1|PA1|always 0
|0|PA0|Interrupt of PROCEED line on/off, set to 0 by OS

To define the data direction of PORT A, set Bit 2 of [PACTL] to 0. Then write a byte to [PORTA], where Bits set to 1 indicate WRITE and Bits set to 0 indicate READ. Normally [PORTA] set to %00000000 (=all input).

see also: [Controller topics|Controller_topics]

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