PIC18F2221 MICROCHIP [Microchip Technology], PIC18F2221 Datasheet - Page 133

• Manufacturer Part Number: PIC18F2221
• Description: 28/40/44-Pin Enhanced Flash Microcontrollers with 10-Bit A/D and nanoWatt Technology
• Manufacturer: MICROCHIP [Microchip Technology]

EXAMPLE 12-1:
TABLE 12-2:
© 2007 Microchip Technology Inc.
INTCON
PIR1
PIE1
IPR1
TMR1L
TMR1H
T1CON
Legend: Shaded cells are not used by the Timer1 module.
Note 1:
RTCinit
RTCisr
Name
These bits are unimplemented on 28-pin devices and read as ‘0’.
Timer1 Register Low Byte
Timer1 Register High Byte
GIE/GIEH PEIE/GIEL
PSPIE
PSPIP
PSPIF
RD16
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
Bit 7
REGISTERS ASSOCIATED WITH TIMER1 AS A TIMER/COUNTER
(1)
(1)
(1)
IMPLEMENTING A REAL-TIME CLOCK USING A TIMER1 INTERRUPT SERVICE
T1RUN
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
ADIF
ADIE
ADIP
Bit 6
T1CKPS1 T1CKPS0 T1OSCEN T1SYNC
TMR0IE
RCIF
RCIE
RCIP
Bit 5
; 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
INT0IE
Preliminary
TXIE
TXIP
Bit 4
TXIF
SSPIF
SSPIE
SSPIP
RBIE
Bit 3
PIC18F4321 FAMILY
TMR0IF
CCP1IF
CCP1IE
CCP1IP
Bit 2
TMR1CS
TMR2IF
TMR2IE
TMR2IP
INT0IF
Bit 1
TMR1ON
TMR1IF
TMR1IE
TMR1IP
RBIF
Bit 0
DS39689E-page 131
on page
Values
Reset
49
52
52
52
50
50
50