MC68HC708MP16 Datasheet, PDF (174/398 Pages) Freescale Semiconductor, Inc – Microcontrollers

Pulse Width Modulator for Motor Control (PWMMC)
9.11.3 PWM X Value Registers
Each of the six PWMs has a 16-bit PWM value register.
PVALXH Bit 7
6
5
4
3
2
1
Bit 0
Read:
Bit 15
14
13
12
11
10
9
Bit 8
Write:
Reset: 0
0
0
0
0
0
0
0
PVALXL Bit 7
6
5
4
3
2
1
Bit 0
Read:
Bit 7
6
5
4
3
2
1
Bit 0
Write:
Reset: 0
0
0
0
0
0
0
0
Figure 9-42. PWM X Value Registers (PVALXH:PVALXL)
The 16-bit signed value stored in this register determines the duty cycle
of the PWM. The duty cycle is defined as: (PWM value/modulus) x 100.
Writing a number less than or equal to zero causes the PWM to be off
for the entire PWM period. Writing a number greater than or equal to the
12-bit modulus causes the PWM to be on for the entire PWM period.
If the complementary mode is selected, the PWM pairs share PWM
value registers.
To avoid erroneous PWM pulses, this value is buffered and will not be
used by the PWM generator until the LDOK bit has been set and the next
PWM load cycle begins.
NOTE: When reading these registers, the value read is the buffer (not
necessarily the value the PWM generator is currently using).
Technical Data
174
MC68HC708MP16 — Rev. 3.1
Pulse Width Modulator for Motor Control (PWMMC) Freescale Semiconductor