160 baud ALDL data - reading on a PC, counter 0?

[Ludis Langens]

Peter Gargano wrote:
> 
> Does anyone know what frequency the AT clocks counter 0 at?
> All my documentation says it's at 0.84 uSec (micro seconds)
> BUT my measurements on a couple of Pentium and 486 machines
> indicate that it's closer to 0.43 uSec AND that it counts
> in lots of 2 (ie. reading counter 0 always reads an even
> binary number).

It sounds like counter 0 is being run in "square wave" mode.  In this
mode, the 8253 counts by twos and toggles the output each time the
counter expires.  If your system uses the 8254, you could use the status
readback to verify this.  (Note - I know next to nothing about Wintel systems...)

-- 
Ludis Langens                               ludis (at) cruzers (dot) com
Mac, Fiero, & engine controller goodies:  http://www.cruzers.com/~ludis/