poweronreset.asm

Alarm clock with PIC microcontroller

;==============================================================================
; Power On Reset
;------------------------------------------------------------------------------


;==============================================================================
; Revision History:
;
; 2005-01-31    Initial version
;------------------------------------------------------------------------------

                include ../pic.inc
                include ../lib/dallas1307.inc
                include display.inc
                include hardware.inc

                errorlevel -302

                global  PowerOnReset

                extern  BeginClocking

;==============================================================================

                code
PowerOnReset:

; Disable PORT B pull ups and /64 prescaler

                banksel OPTION_REG
                movlw   (1<<NOT_RBPU)|(1<<PS2)|(1<<PS0)
                movwf   OPTION_REG

; Configure PORT A as all digital I/O

                banksel ADCON0
                clrf    ADCON1
                banksel ADCON1
                movlw   b'00000111'
                movwf   ADCON1

; Ensure that the SSP module is disabled

                banksel SSPCON
                clrf    SSPCON

; Configure I/O ports and clear latches

                banksel TRISA
                clrf    TRISA
                clrf    TRISB
                clrf    TRISC
                clrf    TRISD
                bsf     TRISD,HZ
                clrf    TRISE
                bsf     TRISE,SW_R
                bsf     TRISE,SW_H
                bsf     TRISE,SW_M

                banksel PORTA
                clrf    PORTA
                clrf    PORTB
                clrf    PORTC
                clrf    PORTD
                clrf    PORTE

; Initialise segment patterns and led, map, buzzer state

                banksel SEG1
                movlw   h'ff'
                movwf   SEG1
                movwf   SEG2
                movwf   SEG3
                movwf   SEG4
                clrf    CTRL

; Set up timer TMR0 to interrupt on roll over.

                banksel TMR0
                clrf    TMR0
                bcf     INTCON,T0IF
                bsf     INTCON,T0IE
                bsf     INTCON,GIE

; Start the real clock I/O processing

                lgoto   BeginClocking

                end