Datasheet

 2010-2016 Microchip Technology Inc. DS40001412G-page 195
PIC18(L)F2X/4XK22
14.4.7 START-UP CONSIDERATIONS
When any PWM mode is used, the application
hardware must use the proper external pull-up and/or
pull-down resistors on the PWM output pins.
The CCPxM<1:0> bits of the CCPxCON register allow
the user to choose whether the PWM output signals are
active-high or active-low for each pair of PWM output
pins (PxA/PxC and PxB/PxD). The PWM output
polarities must be selected before the PWM pin output
drivers are enabled. Changing the polarity
configuration while the PWM pin output drivers are
enable is not recommended since it may result in
damage to the application circuits.
The PxA, PxB, PxC and PxD output latches may not be
in the proper states when the PWM module is
initialized. Enabling the PWM pin output drivers at the
same time as the Enhanced PWM modes may cause
damage to the application circuit.
The Enhanced PWM modes must be enabled in the
proper Output mode and complete a full PWM cycle
before enabling the PWM pin output drivers. The
completion of a full PWM cycle is indicated by the
TMRxIF bit of the PIR1, PIR2 or PIR5 register being set
as the second PWM period begins.
FIGURE 14-19: EXAMPLE OF STEERING EVENT AT END OF INSTRUCTION (STRxSYNC = 0)
FIGURE 14-20: EXAMPLE OF STEERING EVENT AT BEGINNING OF INSTRUCTION
(STRxSYNC = 1)
Note: When the microcontroller is released from
Reset, all of the I/O pins are in the high-
impedance state. The external circuits
must keep the power switch devices in the
Off state until the microcontroller drives
the I/O pins with the proper signal levels or
activates the PWM output(s).
PWM
P1n = PWM
STRx
P1<D:A>
PORT Data
PWM Period
PORT Data
PWM
PORT Data
P1n = PWM
STRx
P1<D:A>
PORT Data