Microchip Technology MCP1630DM-DDBS1 Data Sheet

DS41211D-page 80

©

 2007 Microchip Technology Inc.

11.3.4

OPERATION IN SLEEP MODE

In Sleep mode, the TMR2 register will not increment
and the state of the module will not change. If the CCP1
pin is driving a value, it will continue to drive that value.
When the device wakes up, TMR2 will continue from its
previous state.

11.3.5

CHANGES IN SYSTEM CLOCK 
FREQUENCY

The PWM frequency is derived from the system clock
frequency. Any changes in the system clock frequency
will result in changes to the PWM frequency. See
Section 3.0 “Oscillator Module (With Fail-Safe
Clock Monitor)” for additional details.

11.3.6

EFFECTS OF RESET

Any Reset will force all ports to Input mode and the
CCP registers to their Reset states.

11.3.7

SETUP FOR PWM OPERATION

The following steps should be taken when configuring
the CCP module for PWM operation:

1.

Disable the PWM pin (CCP1) output drivers by
setting the associated TRIS bit.

2.

Set the PWM period by loading the PR2 register.

3.

Configure the CCP module for the PWM mode
by loading the CCP1CON register with the
appropriate values.

4.

Set the PWM duty cycle by loading the CCPR1L
register and DC1B bits of the CCP1CON register.

5.

Configure and start Timer2:

• Clear the TMR2IF interrupt flag bit of the 

PIR1 register.

• Set the Timer2 prescale value by loading the 

T2CKPS bits of the T2CON register.

• Enable Timer2 by setting the TMR2ON bit of 

the T2CON register.

6.

Enable PWM output after a new PWM cycle has
started:

• Wait until Timer2 overflows (TMR2IF bit of 

the PIR1 register is set).

• Enable the CCP1 pin output driver by 

clearing the associated TRIS bit.