PIC18F97J60 Datasheet, PDF (173/474 Pages) Microchip Technology – 64/80/100-Pin, High-Performance, 1 Mbit Flash Microcontrollers with Ethernet

PIC18F97J60 FAMILY
EXAMPLE 12-1: IMPLEMENTING A REAL-TIME CLOCK USING A TIMER1 INTERRUPT SERVICE
RTCinit
RTCisr
MOVLW
MOVWF
CLRF
MOVLW
MOVWF
CLRF
CLRF
MOVLW
MOVWF
BSF
RETURN
BSF
BCF
INCF
MOVLW
CPFSGT
RETURN
CLRF
INCF
MOVLW
CPFSGT
RETURN
CLRF
INCF
MOVLW
CPFSGT
RETURN
CLRF
RETURN
80h
TMR1H
TMR1L
b’00001111’
T1CON
secs
mins
.12
hours
PIE1, TMR1IE
TMR1H, 7
PIR1, TMR1IF
secs, F
.59
secs
secs
mins, F
.59
mins
mins
hours, F
.23
hours
hours
; Preload TMR1 register pair
; for 1 second overflow
; Configure for external clock,
; Asynchronous operation, external oscillator
; Initialize timekeeping registers
;
; Enable Timer1 interrupt
; Preload for 1 sec overflow
; Clear interrupt flag
; Increment seconds
; 60 seconds elapsed?
; No, done
; Clear seconds
; Increment minutes
; 60 minutes elapsed?
; No, done
; clear minutes
; Increment hours
; 24 hours elapsed?
; No, done
; Reset hours
; Done
TABLE 12-2: REGISTERS ASSOCIATED WITH TIMER1 AS A TIMER/COUNTER
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Reset
Values
on page
INTCON GIE/GIEH PEIE/GIEL TMR0IE INT0IE
RBIE TMR0IF INT0IF
RBIF
59
PIR1
PSPIF
ADIF
RC1IF TX1IF SSP1IF CCP1IF TMR2IF TMR1IF
61
PIE1
PSPIE
ADIE
RC1IE TX1IE SSP1IE CCP1IE TMR2IE TMR1IE
61
IPR1
PSPIP
ADIP
RC1IP TX1IP SSP1IP CCP1IP TMR2IP TMR1IP
61
TMR1L Timer1 Register Low Byte
60
TMR1H Timer1 Register High Byte
60
T1CON
RD16 T1RUN T1CKPS1 T1CKPS0 T1OSCEN T1SYNC TMR1CS TMR1ON 60
Legend: Shaded cells are not used by the Timer1 module.
© 2006 Microchip Technology Inc.
Advance Information
DS39762A-page 171