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Chapter 14 Pulse Width Modulator with Fault Protection (PMF15B6CV3)
MC9S12ZVM Family Reference Manual Rev. 1.3
536
Freescale Semiconductor
in center-aligned operation and at the end of cycle in edge-aligned operation. Using this mode requires
external circuitry to sense current direction.
Figure 14-58. Internal Correction Logic when ISENS = 10
Figure 14-59. Internal Correction Logic when ISENS = 11
NOTE
Values latched on the IS
x
inputs are buffered so only one PWM register is
used per PWM cycle. If a current status changes during a PWM period, the
new value does not take effect until the next PWM period.
When initially enabled by setting the PWMEN bit, no current status has previously been sampled. PWM
value registers one, three, and five initially control the three PWM pairs when configured for current status
correction.
Figure 14-60. Correction with Positive Current
D
Q
CLK
PWM CONTROLLED BY
PWM CONTROLLED BY
DEADTIME
GENERATOR
D
Q
CLK
IS
x
PIN
A/B
A
B
PWM CYCLE START
TOP PWM
BOTTOM PWM
INITIAL VALUE = 0
ODD PMFVAL REGISTER
EVEN PMFVAL REGISTER
IN DEADTIME
D
Q
CLK
PWM CONTROLLED BY
PWM CONTROLLED BY
DEADTIME
GENERATOR
D
Q
CLK
IS
x
PIN
A/B
A
B
PWM CYCLE START
TOP PWM
BOTTOM PWM
INITIAL VALUE = 0
ODD PMFVAL REGISTER
EVEN PMFVAL REGISTER
PMFCNT = PMFMOD
DESIRED LOAD VOLTAGE
BOTTOM PWM
LOAD VOLTAGE
TOP PWM