MC9S12P128 Datasheet, PDF (334/564 Pages) Freescale Semiconductor, Inc – S12 Microcontrollers

Pulse-Width Modulator (PWM8B6CV1) Block Description
Table 10-2. PWME Field Descriptions (continued)
Field
1
PWME1
0
PWME0
Description
Pulse Width Channel 1 Enable
0 Pulse width channel 1 is disabled.
1 Pulse width channel 1 is enabled. The pulse modulated signal becomes available at PWM, output bit 1 when
its clock source begins its next cycle.
Pulse Width Channel 0 Enable
0 Pulse width channel 0 is disabled.
1 Pulse width channel 0 is enabled. The pulse modulated signal becomes available at PWM, output bit 0 when
its clock source begins its next cycle. If CON01 = 1, then bit has no effect and PWM output line 0 is disabled.
10.3.2.2 PWM Polarity Register (PWMPOL)
The starting polarity of each PWM channel waveform is determined by the associated PPOLx bit in the
PWMPOL register. If the polarity bit is 1, the PWM channel output is high at the beginning of the cycle
and then goes low when the duty count is reached. Conversely, if the polarity bit is 0 the output starts low
and then goes high when the duty count is reached.
Module Base + 0x0001
7
R
0
W
Reset
0
Read: anytime
6
5
4
3
2
0
PPOL5
PPOL4
PPOL3
PPOL2
0
0
0
0
0
= Unimplemented or Reserved
Figure 10-4. PWM Polarity Register (PWMPOL)
1
PPOL1
0
Write: anytime
NOTE
PPOLx register bits can be written anytime. If the polarity is changed while
a PWM signal is being generated, a truncated or stretched pulse can occur
during the transition
0
PPOL0
0
Table 10-3. PWMPOL Field Descriptions
Field
5
PPOL5
4
PPOL4
Description
Pulse Width Channel 5 Polarity
0 PWM channel 5 output is low at the beginning of the period, then goes high when the duty count is reached.
1 PWM channel 5 output is high at the beginning of the period, then goes low when the duty count is reached.
Pulse Width Channel 4 Polarity
0 PWM channel 4 output is low at the beginning of the period, then goes high when the duty count is reached.
1 PWM channel 4 output is high at the beginning of the period, then goes low when the duty count is reached.
S12P-Family Reference Manual, Rev. 1.12
334
Freescale Semiconductor