PIC18F2420/2520/4420/4520
FIGURE 16-8:
PWM DIRECTION CHANGE
(1)
Period
Period
SIGNAL
P1A (Active-High)
P1B (Active-High)
DC
P1C (Active-High)
P1D (Active-High)
(Note 2)
DC
Note 1: The direction bit in the CCP1 Control register (CCP1CON<7>) is written any time during the PWM cycle.
2: When changing directions, the P1A and P1C signals switch before the end of the current PWM cycle at intervals
of 4 TOSC, 16 TOSC or 64 TOSC, depending on the Timer2 prescaler value. The modulated P1B and P1D signals
are inactive at this time.
FIGURE 16-9:
PWM DIRECTION CHANGE AT NEAR 100% DUTY CYCLE
Forward Period
Reverse Period
t1
(1)
(1)
P1A
P1B
DC
(1)
(1)
P1C
P1D
DC
(2)
t
ON
(1)
(1)
External Switch C
External Switch D
(3)
t
OFF
(2,3)
Potential
t = t
– t
ON
OFF
Shoot-Through
(1)
Current
Note 1: All signals are shown as active-high.
2: t is the turn-on delay of power switch, QC, and its driver.
ON
3: t
is the turn-off delay of power switch, QD, and its driver.
OFF
© 2008 Microchip Technology Inc.
DS39631E-page 155
MICROCHIP [ MICROCHIP ]
