[comp.sys.mac.programmer] Interrupt handler for VIA SY6522 Mac Plus

roelv@hku.uucp (roelv) (02/22/91)

hackers of the world, there's a new one in town!
Could anybody out there help me with my interrupthandler for the VIA SY6522 timer 1 on a Mac plus.
I think I know how to put my handler's address in the Lvl1DT table at offset 24 dec.  I also think I know how to save A5 in my handler's code, and set it up to get to my globals.
I think I know how to put a latch value in VIA's registers.
Knowing all that, it still doesn't work. Should I use the auxiliary control register, and if so, does anybody have some examples?
My sole purpose is to write a counter which increments each millisecond or so, without using Time Manager.
If there's anybody out there who's got such code, would you be willing to share it with me? I'm a C hacker but my brain accepts ASM or Pascal.
ASM is preferred since it's an interrupthandler.

As we say in Holland: "Thanks in advance!!".

Anybody who'd like to send me some e-mail (I'm new at that too) can send their digital postcards to:

**         ****************	
    *     *   *           *           Roel Vertegaal,
     *  *     **         *            Center for Knowledge Technology
       *      *           *           Lange Viestr 2B,3211 PB, Utrecht Holland
       **************                 e-mail <hku!roelv@netherlands.eu.net>
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