murphy@newton.physics.purdue.edu (William J. Murphy) (07/11/90)
Recently, someone posted a unit for using one of the timers in the PC architecture. I compiled it and tried to modify it to create a custom delay function similar to the one(s) supplied by Borland. The timer unit was able to give 10 microsecond interrupts instead of the usual 18.2Hz. Any ways, I had little luck in getting a consistant delay. It seems that there is a rollover that takes place with the timervalue which I don't yet understand. Thus I would be ok for a few cycles then get stomped by a short cycle. What I need is a very accurate delay that won't interrupt a DMA transfer that will always be occuring simultaneously. I am using the delay function to turn on and off a DIO line which connects to a switch which controls my stimulus. The DMA transfer is the A/D conversion of the stimulus plus a signal which is dynamically affected by the stimulus. Does the author of the Timer unit have any suggestions about writing such a delay function? Borland's delay function is accurate to within +- 0.7 milliseconds, as well it has a periodic behaviour in its measured delay. I would be happy if I could get +-0.05 milliseconds standard deviation. Thanks, -- Bill Murphy | Is this a holdup? ... murphy@newton.physics.purdue.edu | No, it's a science experiment. Amiga, it's not a religion, it's a lifestyle | Emmett L. Brown BTF III