MC68HC08AZ0 Datasheet, PDF (306/444 Pages) Motorola, Inc – Advance Information

Freescale Semiconductor, Inc.
Programmable Interrupt Timer (PIT)
POF — PIT overflow flag bit
This read/write flag is set when the PIT counter resets to $0000 after
reaching the modulo value programmed in the PIT counter modulo
registers. Clear POF by reading the PIT status and control register
when POF is set and then writing a logic zero to POF. If another PIT
overflow occurs before the clearing sequence is complete, then
writing logic zero to POF has no effect. Therefore, a POF interrupt
request cannot be lost due to inadvertent clearing of POF. Reset
clears the POF bit. Writing a logic one to POF has no effect.
1 = PIT counter has reached modulo value
0 = PIT counter has not reached modulo value
PIE — PIT overflow interrupt enable bit
This read/write bit enables PIT overflow interrupts when the POF bit
becomes set. Reset clears the PIE bit.
1 = PIT overflow interrupts enabled
0 = PIT overflow interrupts disabled
PSTOP — PIT STOP bit
This read/write bit stops the PIT counter. Counting resumes when
PSTOP is cleared. Reset sets the PSTOP bit, stopping the PIT
counter until software clears the PSTOP bit.
1 = PIT counter stopped
0 = PIT counter active
NOTE: Do not set the PSTOP bit before entering wait mode if the PIT is required
to exit wait mode.
PRST — PIT reset bit
Setting this write-only bit resets the PIT counter and the PIT prescaler.
Setting PRST has no effect on any other registers. Counting resumes
from $0000. PRST is cleared automatically after the PIT counter is
reset and always reads as logic zero. Reset clears the PRST bit.
1 = Prescaler and PIT counter cleared
0 = No effect
NOTE: Setting the PSTOP and PRST bits simultaneously stops the PIT counter
at a value of $0000.
MC68HC08AZ0
304
Programmable Interrupt Timer (PIT)
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6-pit
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