Datasheet

Timer Interface Module (TIM)
MC68HC908QY/QT Family Data Sheet, Rev. 6
132 Freescale Semiconductor
CHxMAX — Channel x Maximum Duty Cycle Bit
When the TOVx bit is at a 1, setting the CHxMAX bit forces the duty cycle of buffered and unbuffered
PWM signals to 100%. As Figure 14-8 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.
Figure 14-8. CHxMAX Latency
14.9.5 TIM Channel Registers
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.
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.
Address: $0026 TCH0H
Bit 7654321Bit 0
Read:
Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit 9 Bit 8
Write:
Reset: Indeterminate after reset
Address:
$0027 TCH0L
Bit 7654321Bit 0
Read:
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Write:
Reset: Indeterminate after reset
Address:
$0029 TCH1H
Bit 7654321Bit 0
Read:
Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit 9 Bit 8
Write:
Reset: Indeterminate after reset
Address:
$02A TCH1L
Bit 7654321Bit 0
Read:
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Write:
Reset: Indeterminate after reset
Figure 14-9. TIM Channel Registers (TCH0H/L:TCH1H/L)
OUTPUT
OVERFLOW
TCHx
PERIOD
CHxMAX
OVERFLOW OVERFLOW OVERFLOW OVERFLOW
COMPARE
OUTPUT
COMPARE
OUTPUT
COMPARE
OUTPUT
COMPARE