PIC18F2682 Datasheet, PDF (183/484 Pages) Microchip Technology – 28/40/44-Pin Enhanced Flash Microcontrollers with ECAN Technology, 10-Bit A/D and nanoWatt Technology

PIC18F2682/2685/4682/4685
FIGURE 16-8:
PWM DIRECTION CHANGE
SIGNAL
Period⁽¹⁾
Period
P1A (Active-High)
P1B (Active-High)
P1C (Active-High)
P1D (Active-High)
DC
DC
(Note 2)
Note 1:
2:
The direction bit in the ECCP1 Control register (ECCP1CON<7>) is written any time during the PWM cycle.
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
t1
Reverse Period
P1A⁽¹⁾
P1B⁽¹⁾
P1C⁽¹⁾
P1D⁽¹⁾
DC
External Switch C⁽¹⁾
External Switch D⁽¹⁾
Potential
Shoot-Through
Current⁽¹⁾
Note 1:
2:
3:
All signals are shown as active-high.
t_ON is the turn-on delay of power switch QC and its driver.
t_OFF is the turn-off delay of power switch QD and its driver.
DC
t_ON⁽²⁾
t_OFF⁽³⁾
t = t_OFF – t_ON^(2,3)
© 2007 Microchip Technology Inc.
Preliminary
DS39761B-page 181