MC68HC908LD64 Datasheet, PDF (168/362 Pages) Freescale Semiconductor, Inc – Microcontrollers

Timer Interface Module (TIM)
TOVx — Toggle-On-Overflow Bit
When channel x is an output compare channel, this read/write bit
controls the behavior of the channel x output when the TIM counter
overflows. When channel x is an input capture channel, TOVx has no
effect. Reset clears the TOVx bit.
1 = Channel x pin toggles on TIM counter overflow.
0 = Channel x pin does not toggle on TIM counter overflow.
NOTE: When TOVx is set, a TIM counter overflow takes precedence over a
channel x output compare if both occur at the same time.
CHxMAX — Channel x Maximum Duty Cycle Bit
When the TOVx bit is at logic one, setting the CHxMAX bit forces the
duty cycle of buffered and unbuffered PWM signals to 100%. As
Figure 11-7 shows, the CHxMAX bit takes effect in the cycle after it
is set or cleared. The output stays at the 100% duty cycle level until
the cycle after CHxMAX is cleared.
OVERFLOW
OVERFLOW
PERIOD
TCHx
OVERFLOW
OVERFLOW
OVERFLOW
CHxMAX
OUTPUT
COMPARE
OUTPUT
COMPARE
OUTPUT
COMPARE
OUTPUT
COMPARE
Figure 11-7. CHxMAX Latency
11.10.5 TIM Channel Registers (TCH0H/L:TCH1H/L)
These read/write registers contain the captured TIM counter value of the
input capture function or the output compare value of the output
compare function. The state of the TIM channel registers after reset is
unknown.
In input capture mode (MSxB:MSxA = 0:0), reading the high byte of the
TIM channel x registers (TCHxH) inhibits input captures until the low
byte (TCHxL) is read.
Data Sheet
168
Timer Interface Module (TIM)
MC68HC908LD64 — Rev. 3.0
Freescale Semiconductor