GM P4 $400x regs

[Mike]

>
>
>> -----Original Message-----
>> Now that I look at these again, I think you're right about 4006 it and the
>> rate at which 4005 counts up - 32.768kHz. At the start of the routine at
>> B38D 4006 is read, #$CD (205) is added to it and the value written back to
>> 4006. 205*30.518uS (the period of 32.768kHz) is 6.25mS or so. This number
>> rings a bell for some reason...where the heck have I heard this
>> number before?
>
>
>2^(16-1) == 32768.  Maximum positive value of the typical implementation for
>a 16 bit signed integer.
>
>
>Regards,
>
>Barry
>

Actually, for a signed 16-bit number, the maximum positive value is 7FFF or
32767. The maximum negative value is FFFF or -32768.

I was actually referring to that 6.25mS timer value. It seems very familiar
in the P4 system but I can't remember why. Interestingly, 6.25mS is the
period of a 160Hz clock (and the slow ALDL rate is 160Hz...but that's
another neat coincidence).

Thanks,

----
Mike