s908gz60cfa Freescale Semiconductor, Inc, s908gz60cfa Datasheet - Page 296

• Manufacturer Part Number: s908gz60cfa
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Timer Interface Module (TIM2)
ELSxB and ELSxA — Edge/Level Select Bits
TOVx — Toggle-On-Overflow Bit
CHxMAX — Channel x Maximum Duty Cycle Bit
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When channel x is an input capture channel, these read/write bits control the active edge-sensing logic
on channel x.
When channel x is an output compare channel, ELSxB and ELSxA control the channel x output
behavior when an output compare occurs.
When ELSxB and ELSxA are both clear, channel x is not connected to port D or port F, and pin
PTDx/T2CHx or pin PTFx/T2CHx is available as a general- purpose I/O pin.
ELSxB and ELSxA work. Reset clears the ELSxB and ELSxA bits.
When channel x is an output compare channel, this read/write bit controls the behavior of the channel
x output when the TIM2 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 a 1 and clear output on compare is selected, setting the CHxMAX bit forces
the duty cycle of buffered and unbuffered PWM signals to 100%. As
bit takes effect in the cycle after it is set or cleared. The output stays at 100% duty cycle level until the
cycle after CHxMAX is cleared.
1 = Channel x pin toggles on TIM2 counter overflow.
0 = Channel x pin does not toggle on TIM2 counter overflow.
PTDx/T2CHx
After initially enabling a TIM2 channel register for input capture operation
and selecting the edge sensitivity, clear CHxF to ignore any erroneous
edge detection flags.
When TOVx is set, a TIM2 counter overflow takes precedence over a
channel x output compare if both occur at the same time.
The 100% PWM duty cycle is defined as a continuous high level if the PWM
polarity is 1 and a continuous low level if the PWM polarity is 0. Conversely,
a 0% PWM duty cycle is defined as a continuous low level if the PWM
polarity is 1 and a continuous high level if the PWM polarity is 0.
CHxMAX
MC68HC908GZ60 • MC68HC908GZ48 • MC68HC908GZ32 Data Sheet, Rev. 6
OVERFLOW
COMPARE
PERIOD
OUTPUT
Figure 19-9. CHxMAX Latency
OVERFLOW
COMPARE
OUTPUT
NOTE
NOTE
NOTE
OVERFLOW
COMPARE
OUTPUT
OVERFLOW
Figure 19-9
COMPARE
OUTPUT
Table 19-2
OVERFLOW
shows, the CHxMAX
Freescale Semiconductor
shows how