Discussion on this thread pricked my memory about some techniques one of the
windows programmers who works with me for generating real time timings for a
life
test rig we were working on.
He forwarded this little snippet with an invitation to mail him if you need
to discuss
it any further.

Regards
Stuart Broad
March, Cambridgeshire, UK.

// This code uses the PC timer chip to delay for 100uS

DelayFor100us()
{
 _outp( 0x61, 0x40 ); // Disable the PC speaker. (Using channel 3 for
timing)
 _outp( 0x43, 0x96 ); // Set timer register
 _outp( 0x42, 0x74 );
 _outp( 0x61, 0x41 ); // GO

 while( _inp( 0x61 ) & 0x20 ){}

 while( _inp( 0x61 ) & 0x20 ){}

 while( _inp( 0x61 ) & 0x20 ){}

 _outp( 0x61, 0x40 );
}

E-Mail me: martind@mcmail.com