Interrupt handling Tutorial

[MartinC]

Hi all,

Could anyone recommend a good tutorial for interrupt handling on the Vic? What I want to do is regularly check a memory location and then update the screen based on what I find, then carry on with normal processing. At a later point I will be wanting to check for keyboard input and processing that.

I've searched this forum and googled, but haven't found a good beginners guide to this based on the Vic 20.

Any help appreciated, as always.

Thanks

Martin

[D-Type]

Post deleted

[Mike]

Could anyone recommend a good tutorial for interrupt handling on the Vic? [...] I've searched this forum and googled, but haven't found a good beginners guide to this based on the Vic 20. [...]

You might want to check out this posting of mine from 2004.

What I want to do is regularly check a memory location and then update the screen based on what I find, then carry on with normal processing. At a later point I will be wanting to check for keyboard input and processing that.

Neither of those two tasks necessarily require the use of interrupts to do the job and for the latter, the KERNAL already provides routines to read the keyboard for application use.

[MartinC]

Thanks Mike, I'll take a look at that. I'm emulating a peripheral, that's why I wanted to explore this approach.

[srowe]

For my own satisfaction (because I can never remember what happens where) I've written a short guide to how interrupts work on the VIC-20 & C64.

https://eden.mose.org.uk/download/Commo ... rrupts.pdf

[chysn]

For my own satisfaction (because I can never remember what happens where) I've written a short guide to how interrupts work on the VIC-20 & C64.

https://eden.mose.org.uk/download/Commo ... rrupts.pdf

It's nice to have everything in one place, thanks!

BRK increments PC by 2 bytes, not 1 as stated in the Software Interrupts section.

[srowe]

It's nice to have everything in one place, thanks!

BRK increments PC by 2 bytes, not 1 as stated in the Software Interrupts section.

I meant to say that the PC is incremented 1 byte after the actual instruction but that isn't clear from the wording. I'll fix that.