Datasheet

Pulse-Width Modulator (S12PWM8B8CV2)
MC9S12G Family Reference Manual, Rev.1.23
642 Freescale Semiconductor
19.3.2.1 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. Once 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 existing PWM channels are disabled (PWMEx–0 = 0), the prescaler counter shuts
off for power savings.
Read: Anytime
Write: Anytime
0x0025
RESERVED
R00 0 00000
W
0x0026
RESERVED
R00 0 00000
W
0x0027
RESERVED
R00 0 00000
W
1
The related bit is available only if corresponding channel exists.
2
The register is available only if corresponding channel exists.
Module Base + 0x0000
76543210
R
PWME7 PWME6 PWME5 PWME4 PWME3 PWME2 PWME1 PWME0
W
Reset 0 0 0 00000
Figure 19-3. PWM Enable Register (PWME)
Register
Name
Bit 7 6 5 4 3 2 1 Bit 0
= Unimplemented or Reserved
Figure 19-2. The scalable PWM Register Summary (Sheet 1 of 4)