MC9S12HZ256 Datasheet, PDF (449/692 Pages) Freescale Semiconductor, Inc – HCS12 Microcontrollers

Chapter 15 Pulse-Width Modulator (PWM8B6CV1)
Table 15-3. PWMPOL Field Descriptions (continued)
Field
2
PPOL2
1
PPOL1
0
PPOL0
Description
Pulse Width Channel 2 Polarity
0 PWM channel 2 output is low at the beginning of the period, then goes high when the duty count is reached.
1 PWM channel 2 output is high at the beginning of the period, then goes low when the duty count is reached.
Pulse Width Channel 1 Polarity
0 PWM channel 1 output is low at the beginning of the period, then goes high when the duty count is reached.
1 PWM channel 1 output is high at the beginning of the period, then goes low when the duty count is reached.
Pulse Width Channel 0 Polarity
0 PWM channel 0 output is low at the beginning of the period, then goes high when the duty count is reached
1 PWM channel 0 output is high at the beginning of the period, then goes low when the duty count is reached.
15.3.2.3 PWM Clock Select Register (PWMCLK)
Each PWM channel has a choice of two clocks to use as the clock source for that channel as described
below.
7
R
0
W
6
5
4
3
2
1
0
PCLK5
PCLK4
PCLK3
PCLK2
PCLK1
Reset
0
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 15-5. PWM Clock Select Register (PWMCLK)
Read: anytime
Write: anytime
NOTE
Register bits PCLK0 to PCLK5 can be written anytime. If a clock select is
changed while a PWM signal is being generated, a truncated or stretched
pulse can occur during the transition.
0
PCLK0
0
Field
5
PCLK5
4
PCLK4
3
PCLK3
Table 15-4. PWMCLK Field Descriptions
Description
Pulse Width Channel 5 Clock Select
0 Clock A is the clock source for PWM channel 5.
1 Clock SA is the clock source for PWM channel 5.
Pulse Width Channel 4 Clock Select
0 Clock A is the clock source for PWM channel 4.
1 Clock SA is the clock source for PWM channel 4.
Pulse Width Channel 3 Clock Select
0 Clock B is the clock source for PWM channel 3.
1 Clock SB is the clock source for PWM channel 3.
MC9S12HZ256 Data Sheet, Rev. 2.04
Freescale Semiconductor
449