mc68hc908gp32 Freescale Semiconductor, Inc, mc68hc908gp32 Datasheet - Page 213

• Manufacturer Part Number: mc68hc908gp32
• Description: M68hc08 Microcontrollers Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

TOVx — Toggle On Overflow Bit
CHxMAX — Channel x Maximum Duty Cycle Bit
17.9.5 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.
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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.
When the TOVx bit is at logic 1, setting the CHxMAX bit forces the duty cycle of buffered and
unbuffered PWM signals to 100%. As
after it is set or cleared. The output stays at the 100% duty cycle level until the cycle after CHxMAX is
cleared.
1 = Channel x pin toggles on TIM counter overflow
0 = Channel x pin does not toggle on TIM counter overflow
CHxMAX
Before enabling a TIM channel register for input capture operation, make
sure that the PTDx/TCHx pin is stable for at least two bus clocks.
When TOVx is set, a TIM counter overflow takes precedence over a
channel x output compare if both occur at the same time.
TCHx
OVERFLOW
COMPARE
PERIOD
OUTPUT
OVERFLOW
Figure 17-11. CHxMAX Latency
MC68HC908GP32 Data Sheet, Rev. 10
Figure 17-11
COMPARE
OUTPUT
NOTE
NOTE
OVERFLOW
shows, the CHxMAX bit takes effect in the cycle
COMPARE
OUTPUT
OVERFLOW
COMPARE
OUTPUT
OVERFLOW
I/O Registers
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