mc68hc908mr32 Freescale Semiconductor, Inc, mc68hc908mr32 Datasheet - Page 133

• Manufacturer Part Number: mc68hc908mr32
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

12.5.4 Output Polarity
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
Figure
Freescale Semiconductor
12-21.
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.
PWM1
PWM2
IS1 POSITIVE
PWM = 1
Figure 12-20. Top/Bottom Correction for PWMs 1 and 2
MC68HC908MR32 • MC68HC908MR16 Data Sheet, Rev. 6.1
PWM VALUE REG. 1 = 1
IS1 POSITIVE
PWM = 1
NOTE
IS1 NEGATIVE
PWM = 2
PWM VALUE REG. 2 = 2
IS1 NEGATIVE
PWM = 2
Output Control
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