PIC18F2450 MICROCHIP [Microchip Technology], PIC18F2450 Datasheet - Page 121

• Manufacturer Part Number: PIC18F2450
• Description: 28/40/44-Pin, High-Performance, 12 MIPS, Enhanced Flash, USB Microcontrollers with nanoWatt Technology
• Manufacturer: MICROCHIP [Microchip Technology]

EXAMPLE 11-1:
TABLE 11-2:
© 2006 Microchip Technology Inc.
INTCON
PIR1
PIE1
IPR1
TMR1L
TMR1H
T1CON
Legend: — = unimplemented, read as ‘0’. Shaded cells are not used by the Timer1 module.
RTCinit
RTCisr
Name
Timer1 Register Low Byte
TImer1 Register High Byte
GIE/GIEH PEIE/GIEL
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
MOVLW
MOVWF
RETURN
RD16
Bit 7
—
—
—
REGISTERS ASSOCIATED WITH TIMER1 AS A TIMER/COUNTER
IMPLEMENTING A REAL-TIME CLOCK USING A TIMER1 INTERRUPT SERVICE
80h
TMR1H
TMR1L
b’00001111’
T1OSC
secs
mins
d’12’
hours
PIE1, TMR1IE ; Enable Timer1 interrupt
TMR1H, 7
PIR1, TMR1IF ; Clear interrupt flag
secs, F
d’59’
secs
secs
mins, F
d’59’
mins
mins
hours, F
d’23’
hours
d’01’
hours
T1RUN
ADIE
ADIP
ADIF
Bit 6
T1CKPS1 T1CKPS0 T1OSCEN T1SYNC
TMR0IE
RCIE
RCIP
RCIF
Bit 5
; Preload TMR1 register pair
; for 1 second overflow
; Configure for external clock,
; Asynchronous operation, external oscillator
; Initialize timekeeping registers
;
; Preload for 1 sec overflow
; 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 to 1
; Done
Advance Information
INT0IE
TXIE
TXIP
Bit 4
TXIF
RBIE
Bit 3
—
—
—
PIC18F2450/4450
TMR0IF
CCP1IF
CCP1IE
CCP1IP
Bit 2
TMR1CS
TMR2IF
TMR2IE
TMR2IP
INT0IF
Bit 1
TMR1ON
TMR1IF
TMR1IE
TMR1IP
RBIF
Bit 0
DS39760A-page 119
on page
Values
Reset
49
51
51
51
50
50
50