Microchip Technology DV164136 Fiche De Données
PIC18F87J11 FAMILY
DS39778E-page 230
2007-2012 Microchip Technology Inc.
FIGURE 19-8:
PWM DIRECTION CHANGE
FIGURE 19-9:
PWM DIRECTION CHANGE AT NEAR 100% DUTY CYCLE
DC
Period
(1)
SIGNAL
Note
1:
The direction bit in the ECCP1 Control register (CCP1CON<7>) is written at 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 T
of 4 T
OSC
, 16 T
OSC
or 64 T
OSC
, depending on the Timer2 prescaler value. The modulated P1B and P1D signals
are inactive at this time.
Period
(Note 2)
P1A (Active-High)
P1B (Active-High)
P1C (Active-High)
P1D (Active-High)
DC
Forward Period
Reverse Period
P1A
(1)
t
ON
(2)
t
OFF
(3)
t = t
OFF
– t
ON
(2,3)
P1B
(1)
P1C
(1)
P1D
(1)
External Switch D
(1)
Potential
Shoot-Through
Current
(1)
Note
1:
All signals are shown as active-high.
2:
t
ON
is the turn-on delay of power switch QC and its driver.
3:
t
OFF
is the turn-off delay of power switch QD and its driver.
External Switch C
(1)
t1
DC
DC