SC9S12XS256J1MAA FREESCALE [Freescale Semiconductor, Inc], SC9S12XS256J1MAA Datasheet - Page 370

• Manufacturer Part Number: SC9S12XS256J1MAA
• Description: HCS12 Microcontrollers
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

Pulse-Width Modulator (S12PWM8B8CV1)
13.3.2.2
The starting polarity of each PWM channel waveform is determined by the associated PPOLx bit in the
PWMPOL register. If the polarity bit is one, 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 zero, the output starts
low and then goes high when the duty count is reached.
Read: Anytime
Write: Anytime
13.3.2.3
Each PWM channel has a choice of two clocks to use as the clock source for that channel as described
below.
370
Module Base + 0x0001
PPOL[7:0]
PWME1
PWME0
Reset
Field
Field
7–0
1
0
W
R
PPOL7
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
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
Pulse Width Channel 7–0 Polarity Bits
0 PWM channel 7–0 outputs are low at the beginning of the period, then go high when the duty count is
1 PWM channel 7–0 outputs are high at the beginning of the period, then go low when the duty count is
PWM Polarity Register (PWMPOL)
PWM Clock Select Register (PWMCLK)
0
7
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
its clock source begins its next cycle. If CON01 = 1, then bit has no effect and PWM output line0 is disabled.
reached.
reached.
its clock source begins its next cycle.
PPOL6
0
6
Table 13-1. PWME Field Descriptions (continued)
Figure 13-4. PWM Polarity Register (PWMPOL)
Table 13-2. PWMPOL Field Descriptions
S12XS Family Reference Manual, Rev. 1.09
PPOL5
0
5
PPOL4
NOTE
0
4
Description
Description
PPOL3
0
3
PPOL2
0
2
PPOL1
Freescale Semiconductor
0
1
PPOL0
0
0