MC68HC908QL4 Datasheet, PDF (185/226 Pages) Motorola, Inc – Microcontrollers

Registers
CHxMAX — Channel x Maximum Duty Cycle Bit
When the TOVx bit is at 1, setting the CHxMAX bit forces the duty cycle of buffered and unbuffered
PWM signals to 100%. As Figure 15-11 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
OVERFLOW
OVERFLOW
OVERFLOW
TCHx
CHxMAX
OUTPUT
COMPARE
OUTPUT
COMPARE
OUTPUT
COMPARE
OUTPUT
COMPARE
Figure 15-11. CHxMAX Latency
15.8.5 TIM Channel Registers
These read/write registers contain the captured 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.
In output compare mode (MSxB:MSxA ≠ 0:0), writing to the high byte of the TIM channel x registers
(TCHxH) inhibits output compares until the low byte (TCHxL) is written.
Bit 7
6
5
4
3
2
1
Bit 0
Read:
Bit 15
Bit 14
Bit 13
Bit 12
Bit 11
Bit 10
Bit 9
Bit 8
Write:
Reset:
Indeterminate after reset
Figure 15-12. TIM Channel x Register High (TCHxH)
Bit 7
6
5
4
3
2
1
Bit 0
Read:
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Write:
Reset:
Indeterminate after reset
Figure 15-13. TIM Channel Register Low (TCHxL)
MC68HC908QL4 Data Sheet, Rev. 7
Freescale Semiconductor
185