matt@srs.UUCP (Matt Goheen) (05/30/85)
A friend of a friend of my boss asked me a little question about
timing things on the Mac. Well, I said "Use the global variable 'Ticks'."
They said, "We need > 5ms resolution." (1/60 sec = 1 tick = about 15ms)
Well, needless to say I'm stuck. I know that there is this little chip
inside the Mac (a Synertek 6522 VIA) and that it supports two timers.
One is used for the sound driver and the other for the disk driver. Both
are available when those drivers are not active (I think). At any rate,
I know that the timer used for the sound driver could be used for other
purposes. I did find some useful info about the VIA inside one of the
assembler include files (like some addresses for its buffers, misc. offsets,
etc....). However, I can't make heads or tails of it. I suppose I could
just get the data sheet for the chip but I know almost nothing about
hardware.
What I'd like to do is just reset a timer, start it and then check
it at various intervals. I assume that poking the correct values
into the correct locations and peeking at the correct locations would
do this just fine. Can someone tell me (please) how to do this (by
email, natch)????
Thanks for the future,
Matt Goheen
S.R. Systems
...seismo!rochester!srs!matt
...no trailer, no disclamer, no quote, no cute picture, no nothing