MC908QL4 FREESCALE [Freescale Semiconductor, Inc], MC908QL4 Datasheet - Page 181

• Manufacturer Part Number: MC908QL4
• Description: M68HC08 Microcontrollers
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

TOIE — TIM Overflow Interrupt Enable Bit
TSTOP — TIM Stop Bit
TRST — TIM Reset Bit
15.8.2 TIM Counter Registers
The two read-only TIM counter registers contain the high and low bytes of the value in the counter.
Reading the high byte (TCNTH) latches the contents of the low byte (TCNTL) into a buffer. Subsequent
reads of TCNTH do not affect the latched TCNTL value until TCNTL is read. Reset clears the TIM counter
registers. Setting the TIM reset bit (TRST) also clears the TIM counter registers.
Freescale Semiconductor
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 15-1
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.
Setting the TSTOP and TRST bits simultaneously stops the counter at a
value of $0000. PS[2:0] — Prescaler Select Bits
PS2
0
0
0
0
1
1
1
1
PS1
0
0
1
1
0
0
1
1
Table 15-1. Prescaler Selection
MC68HC908QL4 Data Sheet, Rev. 7
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)
Registers
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