Chapter 12 Pulse-Width Modulator (PWM8B6CV1) Block Description
Freescale Semiconductor
MC9S12C-Family / MC9S12GC-Family
353
Rev 01.24
12.3.2.1
PWM Enable Register (PWME)
Each PWM channel has an enable bit (PWMEx) to start its waveform output. When any of the PWMEx
bits are set (PWMEx = 1), the associated PWM output is enabled immediately. However, the actual PWM
waveform is not available on the associated PWM output until its clock source begins its next cycle due to
the synchronization of PWMEx and the clock source.
NOTE
The first PWM cycle after enabling the channel can be irregular.
An exception to this is when channels are concatenated. After concatenated mode is enabled (CONxx bits
set in PWMCTL register), enabling/disabling the corresponding 16-bit PWM channel is controlled by the
low-order PWMEx bit. In this case, the high-order bytes PWMEx bits have no effect and their
corresponding PWM output lines are disabled.
While in run mode, if all six PWM channels are disabled (PWME5–PWME0 = 0), the prescaler counter
shuts off for power savings.
Read: anytime
Write: anytime
Module Base + 0x0000
7
6
5
4
3
2
1
0
R
0
0
PWME5
PWME4
PWME3
PWME2
PWME1
PWME0
W
Reset
0
0
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 12-3. PWM Enable Register (PWME)
Table 12-2. PWME Field Descriptions
Field
Description
5
PWME5
Pulse Width Channel 5 Enable
0 Pulse width channel 5 is disabled.
1 Pulse width channel 5 is enabled. The pulse modulated signal becomes available at PWM,output bit 5 when
its clock source begins its next cycle.
4
PWME4
Pulse Width Channel 4 Enable
0 Pulse width channel 4 is disabled.
1 Pulse width channel 4 is enabled. The pulse modulated signal becomes available at PWM, output bit 4 when
its clock source begins its next cycle. If CON45 = 1, then bit has no effect and PWM output line 4 is disabled.
3
PWME3
Pulse Width Channel 3 Enable
0 Pulse width channel 3 is disabled.
1 Pulse width channel 3 is enabled. The pulse modulated signal becomes available at PWM, output bit 3 when
its clock source begins its next cycle.
2
PWME2
Pulse Width Channel 2 Enable
0 Pulse width channel 2 is disabled.
1 Pulse width channel 2 is enabled. The pulse modulated signal becomes available at PWM, output bit 2 when
its clock source begins its next cycle. If CON23 = 1, then bit has no effect and PWM output line 2 is disabled.
Summary of Contents for MC9S12C Family
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