MC68HC08AS32A Datasheet, PDF (253/296 Pages) Motorola, Inc – Microcontrollers

Freescale Semiconductor, Inc.
Timer Interface (TIM)
I/O Registers
NOTE:
NOTE:
Address: $0020
Bit 7
6
5
4
3
Read: TOF
0
0
TOIE TSTOP
Write: 0
TRST
Reset: 0
0
1
0
0
= Unimplemented
2
1
Bit 0
PS2
PS1
PS0
0
0
0
Figure 16-5. TIM Status and Control Register (TSC)
TOF — TIM Overflow Flag Bit
This read/write flag is set when the TIM counter resets reaches the modulo
value programmed in the TIM counter modulo registers. Clear TOF by reading
the TIM status and control register when TOF is set and then writing a logic 0 to
TOF. If another TIM overflow occurs before the clearing sequence is complete,
then writing logic 0 to TOF has no effect. Therefore, a TOF interrupt request
cannot be lost due to inadvertent clearing of TOF. Reset clears the TOF bit.
Writing a logic 1 to TOF has no effect.
1 = TIM counter has reached modulo value
0 = TIM counter has not reached modulo value
TOIE — TIM Overflow Interrupt Enable Bit
This read/write bit enables TIM overflow interrupts when the TOF bit becomes
set. Reset clears the TOIE bit.
1 = TIM overflow interrupts enabled
0 = TIM overflow interrupts disabled
TSTOP — TIM Stop Bit
This read/write bit stops the TIM counter. Counting resumes when TSTOP is
cleared. Reset sets the TSTOP bit, stopping the TIM counter until software
clears the TSTOP bit.
1 = TIM counter stopped
0 = TIM counter active
Do not set the TSTOP bit before entering wait mode if the TIM is required to exit
wait mode. Also when the TSTOP bit is set and the timer is configured for input
capture operation, input captures are inhibited until the TSTOP bit is cleared.
TRST — TIM Reset Bit
Setting this write-only bit resets the TIM counter and the TIM prescaler. Setting
TRST has no effect on any other registers. Counting resumes from $0000.
TRST is cleared automatically after the TIM counter is reset and always reads
as logic 0. Reset clears the TRST bit.
1 = Prescaler and TIM counter cleared
0 = No effect
Setting the TSTOP and TRST bits simultaneously stops the TIM counter at a value
of $0000.
MC68HC08AS32A — Rev. 1
MOTOROLA
Timer Interface (TIM)
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Data Sheet
253