PIC16F883-ESSQTP datasheet(144/338 Pages) MICROCHIP

144 / 338 page

PIC16F882/883/884/886/887

DS41291G-page 144

 2006-2012 Microchip Technology Inc.

11.6.3

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 CCP1M<1:0> bits of the CCP1CON register allow

the user to choose whether the PWM output signals are

active-high or active-low for each pair of PWM output pins

(P1A/P1C and P1B/P1D). 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 P1A, P1B, P1C and P1D 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 TMR2IF bit of the PIR1 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 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).

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