[comp.sys.sun] True speed of Sparc audio chip

MCCABE@MTUS5.BITNET (Jim McCabe) (07/27/90)

I have written a program on the SPARCstation 1 that is designed to
generate extremely accurate frequencies out the headphone jack.  The
program itself works just fine, but I have heard that the Sparc audio chip
doesn't perform at exactly the rate of speed that Sun advertises.

The chip supposedly outputs data at 8000 u-law bytes a second, but I have
heard that a timing crystal (or something like that) is off in all the
Sparcs, pushing performance up to 8095 bytes per second in some cases.

I'd like to know if anyone else has actually checked their Sparcs to see
if this is true.  For this application, it is very important that the
frequency I create is accurate, and so any variation of the output speed
is going to cause a problem.

Is there a method to time the chip using software alone?

Thanks,

-- Jim