mc68hc908qb4 Freescale Semiconductor, Inc, mc68hc908qb4 Datasheet - Page 184

• Manufacturer Part Number: mc68hc908qb4
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Timer Interface Module (TIM)
TOIE — TIM Overflow Interrupt Enable Bit
TSTOP — TIM Stop Bit
TRST — TIM Reset Bit
PS[2:0] — Prescaler Select Bits
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effect. Therefore, a TOF interrupt request cannot be lost due to inadvertent clearing of TOF. Writing a
1 to TOF has no effect.
This read/write bit enables TIM overflow interrupts when the TOF bit becomes set.
This read/write bit stops the counter. Counting resumes when TSTOP is cleared. Reset sets the
TSTOP bit, stopping the counter until software clears the TSTOP bit.
Setting this write-only bit resets the counter and the TIM prescaler. Setting TRST has no effect on any
other timer registers. Counting resumes from $0000. TRST is cleared automatically after the counter
is reset and always reads as 0.
These read/write bits select one of the seven prescaler outputs as the input to the counter as
Table 16-1
1 = Counter has reached modulo value
0 = Counter has not reached modulo value
1 = TIM overflow interrupts enabled
0 = TIM overflow interrupts disabled
1 = Counter stopped
0 = Counter active
1 = Prescaler and counter cleared
0 = No effect
shows.
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.
When using TSTOP to stop the timer counter, see if any timer flags are set.
If a timer flag is set, it must be cleared by clearing TSTOP, then clearing the
flag, then setting TSTOP again.
Setting the TSTOP and TRST bits simultaneously stops the counter at a
value of $0000.
PS2
0
0
0
0
1
1
1
1
PS1
0
0
1
1
0
0
1
1
Table 16-1. Prescaler Selection
MC68HC908QB8 Data Sheet, Rev. 2
PS0
0
1
0
1
0
1
0
1
NOTE
NOTE
Internal bus clock ÷ 16
Internal bus clock ÷ 32
Internal bus clock ÷ 64
Internal bus clock ÷ 1
Internal bus clock ÷ 2
Internal bus clock ÷ 4
Internal bus clock ÷ 8
TIM Clock Source
TCLK (if available)
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