cbscpe wrote:
Even if the actual frequency of the interrupt is 128Hz and not 100Hz it still can be used, you just need to take that into account, or am I wrong on this?
If you are using a counter that is incremented or decremented with each jiffy you simply start at
$00 or
$80 and go from there. In the former case, when it hits
$80 or in the latter case, when it hits
$00, you'd reset the jiffy count and bump the seconds.
As long as the jiffy count has no special meaning to anything other than the routine that maintains the time, I don't see any reason why an odd interrupt rate would be a handicap. That said, the POC's BIOS returns the instantaneous jiffy count when the
GESUTIM (get system uptime) function is called, which gives the uptime a 10 millisecond resolution. For that reason, use of a time base that increments exactly at 10 millisecond intervals is necessary if the return count is to be accurate. That's where the counter/timer in the 28L92 comes in.