mc68hc908mr24 Freescale Semiconductor, Inc, mc68hc908mr24 Datasheet - Page 159

• Manufacturer Part Number: mc68hc908mr24
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

9.6.4 Output Polarity
MC68HC908MR24 — Rev. 4.1
Freescale Semiconductor
UP/DOWN COUNTER
MODULUS = 4
NOTE:
PWM <= 0
PWM >= 4
PWM = 1
PWM = 2
PWM = 3
Center-Aligned Positive 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
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)
Figure 9-20. PWM Polarity
Pulse-Width Modulator for Motor Control (PWMMC)
UP-ONLY COUNTER
Edge-Aligned Positive Polarity
MODULUS = 4
PWM <= 0
PWM >= 4
PWM = 1
PWM = 2
PWM = 3
Advance Information
Figure
9-20.
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