TGB1718 Posted June 5, 2020 Share Posted June 5, 2020 I know PORTA can be set to use an IRQ by setting a bit in PACTL register, but I can't find any information about a vector for the IRQ or how to set the IRQ to process your code. I've looked though many books and manual, and lots say it's there, but not how to use it. Any pointers will be much appreciated Quote Link to comment Share on other sites More sharing options...
Kyle22 Posted June 5, 2020 Share Posted June 5, 2020 From Mapping the Atari: 514,515 202,203 VPRCED Serial (peripheral) proceed line vector, initialized to 59314 ($E7B2), which is merely a PLA, RTI instruction sequence. It is used when an IRQ interrupt occurs due to the serial I/O bus proceed line which is available for peripheral use. According to De Re Atari, this interrupt is not used and points to a PLA, RTI instruction sequence. This interrupt is handled by the PIA chip and can be used to provide more control over external devices. See the OS Listing, page 33. 516,517 204,205 VINTER Serial (peripheral) interrupt vector, initialized to 59314 ($E7B2). Used for the IRQ interrupt due to a serial bus I/O interrupt. According to De Re Atari, this interrupt is not used and points to a PLA, RTI sequence. This interrupt is processed by PIA. See the OS Listing, page 33. Quote Link to comment Share on other sites More sharing options...
Wrathchild Posted June 5, 2020 Share Posted June 5, 2020 (edited) Could be VPRCED @ $202 C0A0: 68 PLA C0A1: AA TAX C0A2: 2C 02 D3 BIT PACTL C0A5: 10 06 BPL $C0AD C0A7: AD 00 D3 LDA PORTA C0AA: 6C 02 02 JMP (VPRCED) [Edit] ah, crossed over in posting - but I suspect the OP might be asking for something like transition on pin type IRQs? Edited June 5, 2020 by Wrathchild Quote Link to comment Share on other sites More sharing options...
TGB1718 Posted June 5, 2020 Author Share Posted June 5, 2020 Thanks, will check it out Quote Link to comment Share on other sites More sharing options...
xxl Posted June 5, 2020 Share Posted June 5, 2020 (edited) the operating system is not prepared for some interrupts from PIA. try: POKE 54018,48 POKE 54018,24 Edited June 5, 2020 by xxl 1 Quote Link to comment Share on other sites More sharing options...
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