MC68HC11KW1 Datasheet, PDF (180/238 Pages) Motorola, Inc – High-density complementary metal oxide semiconductor HCMOS) microcontroller unit

PR3A and PR3B — Timer 3 prescaler select
These bits are used to select the prescaler divide-by ratio for Timer 3. They can only be written to
once after reset. If PR3B and PR3A are both cleared, then Timer 3 is synchronized to the
prescaled Timer 1 rate, which is determined by the PR1 and PR0 bits in the TMSK2 register. See
Section 9.1.3.9 and Figure 9-1.
PR3B
0
0
1
1
PR3A
0
1
0
1
Prescaler
Use Timer 1 rate
1
4
16
ECEB and ECEA — Event counter edge control
These control bits configure the input clock source for the Timer 3 counter. They can be written to
only once after reset.
ECEB
0
0
1
1
ECEA
0
1
0
1
Configuration
Timer 2 uses internal clock and prescaler
Count on rising edges of external clock only
Count on falling edges of external clock only
Count on any edge of external clock
9
T3STP — Stop Timer 3 counter
1 (set) – Timer 3 counter and prescaler are stopped and the counter is reset
to $0000.
0 (clear) – Timer 3 counter operates normally.
I1/O4 — Input capture 1/output compare 4
1 (set) – Input capture 1 function is enabled (no OC4)
0 (clear) – Output compare 4 function is enabled (no IC1)
9-28
TIMING SYSTEM
MC68HC11KW1