mc68hc708mp16 Freescale Semiconductor, Inc, mc68hc708mp16 Datasheet - Page 156

• Manufacturer Part Number: mc68hc708mp16
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Pulse Width Modulator for Motor Control (PWMMC)
9.6.4 Output Polarity
Technical Data
156
NOTE:
The output polarity of the PWMs is determined by two options: TOPNEG
and BOTNEG. The top polarity option, TOPNEG, controls the polarity of
PWMs 1, 3, and 5. The bottom polarity option, BOTNEG, controls the
polarity of PWMs 2, 4, and 6. Positive polarity means that when the PWM
is active, the PWM output is high. Conversely, negative polarity means
that when the PWM is active, PWM output is low. See
Section 5. Configuration Register
Both bits are found in the CONFIG register, which is a write-once
register. This reduces the chances of the software inadvertently
changing the polarity of the PWM signals and possibly damaging the
motor drive hardware.
Pulse Width Modulator for Motor Control (PWMMC)
DESIRED LOAD VOLTAGE
DESIRED LOAD VOLTAGE
Figure 9-26. Correction with Negative Current
Figure 9-25. Correction with Positive Current
LOAD VOLTAGE
LOAD VOLTAGE
BOTTOM PWM
BOTTOM PWM
TOP PWM
TOP PWM
(CONFIG).
MC68HC708MP16
Freescale Semiconductor
Figure 9-27
—
Rev. 3.1
and