s908ey8ad4cfjer Freescale Semiconductor, Inc, s908ey8ad4cfjer Datasheet - Page 202

• Manufacturer Part Number: s908ey8ad4cfjer
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Timer Interface A (TIMA) Module
TOIE — TIMA Overflow Interrupt Enable Bit
TSTOP — TIMA Stop Bit
TRST — TIMA Reset Bit
PS[2:0] — Prescaler Select Bits
202
This read/write bit enables TIMA overflow interrupts when the TOF bit becomes set. Reset clears the
TOIE bit.
This read/write bit stops the TIMA counter. Counting resumes when TSTOP is cleared. Reset sets the
TSTOP bit, stopping the TIMA counter until software clears the TSTOP bit.
Setting this write-only bit resets the TIMA counter and the TIMA prescaler. Setting TRST has no effect
on any other registers. Counting resumes from $0000. TRST is cleared automatically after the TIMA
counter is reset and always reads as 0. Reset clears the TRST bit.
These read/write bits select one of the seven prescaler outputs as the input to the TIMA counter as
Table 17-1
1 = TIMA overflow interrupts enabled
0 = TIMA overflow interrupts disabled
1 = TIMA counter stopped
0 = TIMA counter active
1 = Prescaler and TIMA counter cleared
0 = No effect
shows. Reset clears the PS[2:0] bits.
Do not set the TSTOP bit before entering wait mode if the TIMA 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
TSTOP is cleared.
When using TSTOP to stop the timer counter, check for any timer flags
being 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 TIMA counter
at a value of $0000.
MC68HC908EY16 • MC68HC908EY8 Data Sheet, Rev. 10
PS[2:0]
0 0 0
0 0 1
0 1 0
0 1 1
1 0 0
1 0 1
1 1 0
1 1 1
Table 17-1. Prescaler Selection
NOTE
NOTE
Internal bus clock ÷ 16
Internal bus clock ÷ 32
Internal bus clock ÷ 64
Internal bus clock ÷ 1
Internal bus clock ÷ 4
Internal bus clock ÷ 2
Internal bus clock ÷ 8
TIMA Clock Source
Unused
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