PIC18F23K22 Datasheet, PDF (199/492 Pages) Microchip Technology – 28/40/44-Pin, Low-Power, High-Performance Microcontrollers with nanoWatt XLP Technology

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.
Note:
When the microcontroller is released from
Reset, all of the I/O pins are in the
high-impedance state. The external cir-
cuits 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).
FIGURE 14-19: EXAMPLE OF STEERING EVENT AT END OF INSTRUCTION (STRxSYNC = 0)
PWM
PWM Period
STRx
P1<D:A>
PORT Data
P1n = PWM
PORT Data
FIGURE 14-20:
EXAMPLE OF STEERING EVENT AT BEGINNING OF INSTRUCTION
(STRxSYNC = 1)
PWM
STRx
P1<D:A>
PORT Data
P1n = PWM
PORT Data
 2010 Microchip Technology Inc.
Preliminary
DS41412B-page 199