mc68hc908mr24 Freescale Semiconductor, Inc, mc68hc908mr24 Datasheet - Page 158

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

Pulse-Width Modulator for Motor Control
Advance Information
158
NOTE:
Distortion correction is only available in complementary mode. At the
beginning of the PWM period, the PWM uses this latched current value
or polarity bit to decide whether the top PWM value or bottom PWM
value is used.
for PWMs 1 and 2.
The IPOLx bits and the values latched on the ISx pins are buffered so
that only one PWM register is used per PWM cycle. If the IPOLx bits or
the current sense values change during a PWM period, this new value
will not be used until the next PWM period. The ISENSx bits are NOT
buffered; therefore, changing the current sensing method could affect
the present PWM cycle.
When the PWM is first enabled by setting PWMEN, PWM value registers
1, 3, and 5 will be used if the ISENSx bits are configured for current
sensing correction. This is because no current will have previously been
sensed.
PWM1
PWM2
Pulse-Width Modulator for Motor Control (PWMMC)
IS1 POSITIVE
PWM = 1
Figure 9-19. Top/Bottom Correction for PWMs 1 and 2
Figure 9-19
PWM VALUE REG. 1 = 1
IS1 POSITIVE
PWM = 1
shows an example of top/bottom correction
IS1 NEGATIVE
PWM = 2
PWM VALUE REG. 2 = 2
MC68HC908MR24
IS1 NEGATIVE
Freescale Semiconductor
PWM = 2
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Rev. 4.1