The Zilog KIO

I'm finally able to start working again after a couple of flat moves and slap bang into another wall. A Z84C90 shaped wall. I couldn't find a worked example of KIO code and the documentation is sparse. Most of the components are covered in examples for the stand-alone chips but not the KIO Command Register.

 This is all you get.

 


I thought I was writing the register as it says it must be done put not only must you write to the registers you must have D3 set to 1 or no interrupts.

KIO_INIT:
    .ifdef Z84C15
    .else
    ld    A,01111011B    ; SIOPIA Mode = PIA, Reset SIO, Reset CTC, Reset PIO, Daisy chain write enable, Daischain = CTC,SIO,PIO
    ld    BC,KIOCMDA
    out    (BC),A
    .endif


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