MC68HC708XL36 FREESCALE [Freescale Semiconductor, Inc], MC68HC708XL36 Datasheet - Page 182

• Manufacturer Part Number: MC68HC708XL36
• Description: HCMOS Microcontroller Unit
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

TIM
PWM Initialization
MC68HC708XL36
182
NOTE:
NOTE:
In buffered PWM signal generation, do not write new pulse width values
to the currently active channel registers. Writing to the active channel
registers is the same as generating unbuffered PWM signals.
To ensure correct operation when generating unbuffered or buffered
PWM signals, use the following initialization procedure:
In PWM signal generation, do not program the PWM channel to toggle
on output compare. Toggling on output compare prevents reliable 0%
duty cycle generation and removes the ability of the channel to
self-correct in the event of software error or noise. Toggling on output
compare can also cause incorrect PWM signal generation when
changing the PWM pulse width to a new, much larger value.
1. In the TIM status and control register (TSC):
2. In the TIM counter modulo registers (TMODH:TMODL), write the
3. In the TIM channel x registers (TCHxH:TCHxL), write the value for
4. In TIM channel x status and control register (TSCx):
5. In the TIM status control register (TSC), clear the TIM stop bit,
Freescale Semiconductor, Inc.
For More Information On This Product,
a. Stop the TIM counter by setting the TIM stop bit, TSTOP.
b. Reset the TIM counter by setting the TIM reset bit, TRST.
value for the required PWM period.
the required pulse width.
a. Write 0:1 (for unbuffered output compare or PWM signals) or
b. Write 1 to the toggle-on-overflow bit, TOVx.
c. Write 1:0 (to clear output on compare) or 1:1 (to set output on
TSTOP.
1:0 (for buffered output compare or PWM signals) to the mode
select bits, MSxB:MSxA. See
compare) to the edge/level select bits, ELSxB:ELSxA. The
output action on compare must force the output to the
complement of the pulse width level. See
197.
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TIM
Table 4
on page 197.
Table 4
on page
MOTOROLA
12-tim4_b