MC908MR16CFUE Datasheet, PDF (245/282 Pages) Freescale Semiconductor, Inc – On-chip programming firmware for use with host personal computer, Clock generator module (CGM)

I/O Registers
TSTOP — TIMB Stop Bit
This read/write bit stops the TIMB counter. Counting resumes when TSTOP is cleared. Reset sets the
TSTOP bit, stopping the TIMB counter until software clears the TSTOP bit.
1 = TIMB counter stopped
0 = TIMB counter active
NOTE
Do not set the TSTOP bit before entering wait mode if the TIMB 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.
TRST — TIMB Reset Bit
Setting this write-only bit resets the TIMB counter and the TIMB prescaler. Setting TRST has no effect
on any other registers. Counting resumes from $0000. TRST is cleared automatically after the TIMB
counter is reset and always reads as logic 0. Reset clears the TRST bit.
1 = Prescaler and TIMB counter cleared
0 = No effect
NOTE
Setting the TSTOP and TRST bits simultaneously stops the TIMB counter
at a value of $0000.
PS[2:0] — Prescaler Select Bits
These read/write bits select either the PTE0/TCLKB pin or one of the seven prescaler outputs as the
input to the TIMB counter as Table 17-1 shows. Reset clears the PS[2:0] bits.
Table 17-1. Prescaler Selection
PS[2:0]
000
001
010
011
100
101
110
111
TIMB Clock Source
Internal bus clock ÷1
Internal bus clock ÷ 2
Internal bus clock ÷ 4
Internal bus clock ÷ 8
Internal bus clock ÷ 16
Internal bus clock ÷ 32
Internal bus clock ÷ 64
PTE0/TCLKB
MC68HC908MR32 • MC68HC908MR16 Data Sheet, Rev. 6.1
Freescale Semiconductor
245