s908ey8ad4cfjer Freescale Semiconductor, Inc, s908ey8ad4cfjer Datasheet - Page 222

• Manufacturer Part Number: s908ey8ad4cfjer
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Timer Interface B (TIMB) Module
TOVx — Toggle-On-Overflow Bit
CHxMAX — Channel x Maximum Duty Cycle Bit
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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 TIMB 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 1 and clear output on compare is selected, setting the CHxMAX bit forces the
duty cycle of buffered and unbuffered PWM signals to 100 percent. As
CHxMAX bit takes effect in the cycle after it is set or cleared. The output stays at 100 percent duty
cycle level until the cycle after CHxMAX is cleared.
1 = Channel x pin toggles on TIMB counter overflow.
0 = Channel x pin does not toggle on TIMB counter overflow.
PTEx/TCHx
When TOVx is set, a TIMB counter overflow takes precedence over a
channel x output compare if both occur at the same time.
The PWM 100 percent duty cycle is defined as output high all of the time.
To generate the 100 percent duty cycle, use the CHxMAX bit in the TSCx
register. The PWM 0 percent duty cycle is defined as output low all of the
time. To generate the 0 percent duty cycle, select clear output on compare
and then clear the TOVx bit (CHxMAX = 0).
CHxMAX
TOV = 1
TOV = 0
OVERFLOW
MC68HC908EY16 • MC68HC908EY8 Data Sheet, Rev. 10
COMPARE
PERIOD
OUTPUT
Figure 18-8. CHxMAX Latency
OVERFLOW
COMPARE
OUTPUT
NOTE
NOTE
OVERFLOW
COMPARE
OUTPUT
OVERFLOW
COMPARE
OUTPUT
Figure 18-8
OVERFLOW
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