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in libcpu/powerpc/mpc860/clock/clock.c:InstallClock() the reload value for
the PIT is defined as:
pit_value = (BSP_Configuration.microseconds_per_tick *
Cpu_table.clicks_per_usec) - 1 ;
What exactly is a tick, and what is a click?
My confusion stems from the fact, that Jay defines clicks_per_usec to 1
which is correct for his configuration, where a 4MHz clock is predivided
by 4 and then fed to the PIT. So I assume a "click" is just the period of
the PIT input frequency.
However, our HW config seems to have 32.768 kHz crystal input for PIT.
Mandatory division by 4 means 8.196kHz (122usec) at the PIT.
I think, the above assignment should read:
pit_value = (BSP_Configuration.microseconds_per_tick /
Cpu_table.clicks_per_usec) - 1;
where I can define Cpu_table.clicks_per_usec in bspstart.c to 122
(clicks_per_usec). That would lead to a PIT reload value of
10000/122 - 1 = 81 to reach a 10ms "tick" period.
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