jslackey@kilroy.Jpl.Nasa.Gov (Jesse S. Lackey) (08/03/90)
hi. I'm just getting started w/amiga programming, and I want to make a dirt cheap digitizer as a simple digital 'scope. On page 331 in the Amiga Hardware Reference Manual there is a sample program which shuts off all interrupts, then blinks the LED at 3ms intervals using one of the 8520 timers. I wrote a (hopefully) equivalent program in C (lattice 5.0) but it doesn't do anything at all. If I use another timer (timer A on CIAB) and don't shut off interrupts, it will work - but is very erratic due to the task switching going on. questions: 1. Does the c.o lattice C startup file require interrupts to operate? I looked at the code out of LC and it seemed to be straightforward. 2. When interrupts are shut off by move.w #$7fff,dmacon(a3) with a3= addr of custom chips, does any task switching occur? Any and all help is appreciated. jslackey@grissom.jpl.nasa.gov