COCO interrupt examples

[Rastamafugg]

Is there a good source for code examples using the various interrupts available for the Coco?  Preferably Basic09/Nitros9 examples, but I'm having trouble finding anything online other than what is documented in the service manual documentation.  I'm particularly interested in inserting code to run when the HSYNC and VSYNC interrupts trigger, but I can't seem to find any examples or tutorials for Coco interrupt handling in general.

[Michael Kline]

I don't have the answer to your question. I can lead you to other resources and people who may know. These places are much more popular than here.

 

FB OS9/NITROS9 Group: https://www.facebook.com/groups/1929079184021683/

FB Colour Computer Group: https://www.facebook.com/groups/2359462640/

 

CoCo Discord: https://discord.gg/4J5nHXm

 

The Colour Computer Archive IS the online resource to know about: https://colorcomputerarchive.com/ Search for books and manuals there. Software is available there too.

 

Michael

 

 

[Rastamafugg]

I located some assembly books for the coco.  I think what I'm looking for is registering an interrupt handler for IRQ, which fires 60 times a second.  If I'm reading that correctly, though, does that mean the IRQ interrupt fires at the same point in the display cycle?  And is that predictable? (eg: start of the vertical blank?) 

 

I'll try asking some of the sources Michael linked to above, as well.

[MrDave]

xVsync.   LDA $FF02

vlop.        LDA $FF03

                Cmpa.  #128

                BLO.  vlop

                Rts

 

IF This subroutine is called it will wait for vsync signal.   I think its tied to the field sync signal on the vdg

[MrDave]

You can swap the cmpa 128 blo to

BPL. 

 

I use this code in my programs so it will run the same speed even if you overclock vcc 

 

[MarkO]

On 5/30/2022 at 7:23 AM, Rastamafugg said:

Is there a good source for code examples using the various interrupts available for the Coco?  Preferably Basic09/Nitros9 examples, but I'm having trouble finding anything online other than what is documented in the service manual documentation.  I'm particularly interested in inserting code to run when the HSYNC and VSYNC interrupts trigger, but I can't seem to find any examples or tutorials for Coco interrupt handling in general.

The CoCo Discord has one of NitrOS9's Progenitors, L. Curtis Boyle as an Administrator..  And another NitrOS9 Progenitor, Bill Nobel, who frequents the OS9 Channels....

 

And then there is MrDave....... 

 

MarkO  ( CoCoNUT! since 2012  )