Microchip Technology DM164134 数据表
© 2006 Microchip Technology Inc.
DS41159E-page 139
PIC18FXX8
FIGURE 16-7:
PWM DIRECTION CHANGE
FIGURE 16-8:
PWM DIRECTION CHANGE AT NEAR 100% DUTY CYCLE
DC
Period
(1)
SIGNAL
Note
1:
The direction bit in the ECCP1 Control Register (ECCP1CON.EPWM1M1) is written any time during the PWM
cycle.
cycle.
2: The P1A and P1C signals switch at intervals of T
OSC
, 4 T
OSC
or 16 T
OSC
, depending on the Timer2 prescaler
value earlier when changing direction. The modulated P1B and P1D signals are inactive at this time.
Period
(2)
P1A (Active-High)
P1B (Active-High)
P1C (Active-High)
P1D (Active-High)
Forward Period
Reverse Period
(PWM)
P1A
(1)
(PWM)
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 and driver.
3: t
off
is the turn-off delay of power switch and driver.
External Switch C
(1)
t1