PIC16C72-02E/SP View Datasheet(PDF) - Microchip Technology

Part Name

Description

Manufacturer

PIC16C72-02E/SP

8-Bit CMOS microcontroller with A,D converter

Microchip Technology 

For an example PWM period and duty cycle calcula-

tion, see the PICmicro™ Mid-Range MCU Reference

Manual (DS33023).

7.3.3 SET-UP FOR PWM OPERATION

The following steps should be taken when configuring

the CCP module for PWM operation:

1. Set the PWM period by writing to the PR2 regis-

ter.

2. Set the PWM duty cycle by writing to the

CCPR1L register and CCP1CON<5:4> bits.

PIC16C72 Series

3. Make the CCP1 pin an output by clearing the

TRISC<2> bit.

4. Set the TMR2 prescale value and enable Timer2

by writing to T2CON.

5. Configure the CCP1 module for PWM operation.

TABLE 7-3 EXAMPLE PWM FREQUENCIES AND RESOLUTIONS AT 20 MHz

PWM Frequency

Timer Prescaler (1, 4, 16)

PR2 Value

Maximum Resolution (bits)

1.22 kHz 4.88 kHz 19.53 kHz 78.12 kHz 156.3 kHz 208.3 kHz

16

0xFF

10

4

0xFF

10

1

0xFF

10

1

0x3F

8

1

0x1F

7

1

0x17

5.5

TABLE 7-4 REGISTERS ASSOCIATED WITH PWM AND TIMER2

Address Name

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

Value on:

POR,

BOR

Value on

all other

resets

0Bh,8Bh

0Ch

8Ch

INTCON

PIR1

PIE1

GIE

PEIE

T0IE

INTE

RBIE

T0IF

INTF

RBIF 0000 000x 0000 000u

(1)

ADIF

(1)

(1)

SSPIF CCP1IF TMR2IF TMR1IF 0000 0000 0000 0000

(1)

ADIE

(1)

(1)

SSPIE CCP1IE TMR2IE TMR1IE 0000 0000 0000 0000

87h

TRISC PORTC Data Direction Register

1111 1111 1111 1111

11h

TMR2

Timer2 module’s register

0000 0000 0000 0000

92h

PR2

Timer2 module’s period register

1111 1111 1111 1111

12h

T2CON

— TOUTPS TOUTPS TOUTPS TOUTPS TMR2O T2CKPS T2CKPS -000 0000 -000 0000

3

2

1

0

N

1

0

15h

CCPR1L Capture/Compare/PWM register1 (LSB)

xxxx xxxx uuuu uuuu

16h

CCPR1H Capture/Compare/PWM register1 (MSB)

xxxx xxxx uuuu uuuu

17h

CCP1CON —

—

CCP1X CCP1Y CCP1M3 CCP1M2 CCP1M1 CCP1M0 --00 0000 --00 0000

Legend: x = unknown, u = unchanged, - = unimplemented read as '0'. Shaded cells are not used by PWM and Timer2.

Note 1: These bits/registers are unimplemented, read as '0'.

© 1998 Microchip Technology Inc.

Preliminary

DS39016A-page 37

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