PIC18F258-I/SP View Datasheet(PDF) - Microchip Technology

Part Name

Description

Manufacturer

PIC18F258-I/SP

28/40-Pin High-Performance, Enhanced Flash Microcontrollers with CAN Module

Microchip Technology 

PIC18FXX8

13.2 Timer2 Interrupt

The Timer2 module has an 8-bit period register, PR2.

Timer2 increments from 00h until it matches PR2 and

then resets to 00h on the next increment cycle. PR2 is

a readable and writable register. The PR2 register is

initialized to FFh upon Reset.

FIGURE 13-1:

TIMER2 BLOCK DIAGRAM

13.3 Output of TMR2

The output of TMR2 (before the postscaler) is a clock

input to the Synchronous Serial Port module which

optionally uses it to generate the shift clock.

TMR2

Output(1)

Sets Flag

bit TMR2IF

FOSC/4

Prescaler

1:1, 1:4, 1:16

2

T2CKPS1:T2CKPS0

TMR2

Reset

Comparator

Postscaler

EQ 1:1 to 1:16

PR2

4

TOUTPS3:TOUTPS0

Note 1: TMR2 register output can be software selected by the SSP module as a baud clock.

TABLE 13-1: REGISTERS ASSOCIATED WITH TIMER2 AS A TIMER/COUNTER

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

INTCON

PIR1

PIE1

IPR1

GIE/GIEH

PSPIF(1)

PSPIE(1)

PSPIP(1)

PEIE/GIEL

ADIF

ADIE

ADIP

TMR0IE

RCIF

RCIE

RCIP

INT0IE

TXIF

TXIE

TXIP

RBIE

SSPIF

SSPIE

SSPIP

TMR0IF

CCP1IF

CCP1IE

CCP1IP

INT0IF

TMR2IF

TMR2IE

TMR2IP

RBIF

TMR1IF

TMR1IE

TMR1IP

0000 000x 0000 000u

0000 0000 0000 0000

0000 0000 0000 0000

1111 1111 1111 1111

TMR2 Timer2 Module Register

0000 0000 0000 0000

T2CON

—

TOUTPS3 TOUTPS2 TOUTPS1 TOUTPS0 TMR2ON T2CKPS1 T2CKPS0 -000 0000 -000 0000

PR2 Timer2 Period Register

1111 1111 1111 1111

Legend: x = unknown, u = unchanged, - = unimplemented, read as ‘0’. Shaded cells are not used by the Timer2 module.

Note 1: These registers or register bits are not implemented on the PIC18F248 and PIC18F258 and read as ‘0’s.

DS41159E-page 118

© 2006 Microchip Technology Inc.

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