;**********************************************************************
;   This file is a basic code template for assembly code generation   *
;   on the PICmicro PIC16F677. This file contains the basic code      *
;   building blocks to build upon.                                    *
;                                                                     *
;   If interrupts are not used all code presented between the ORG     *
;   0x004 directive and the label main can be removed. In addition    *
;   the variable assignments for 'w_temp' and 'status_temp' can       *
;   be removed.                                                       *
;                                                                     *
;   Refer to the MPASM User's Guide for additional information on     *
;   features of the assembler (Document DS33014).                     *
;                                                                     *
;   Refer to the respective PICmicro data sheet for additional        *
;   information on the instruction set.                               *
;                                                                     *
;**********************************************************************
;                                                                     *
;    Filename:	    xxx.asm                                           *
;    Date:                                                            *
;    File Version:                                                    *
;                                                                     *
;    Author:                                                          *
;    Company:                                                         *
;                                                                     *
;                                                                     *
;**********************************************************************
;                                                                     *
;    Files required:                                                  *
;                                                                     *
;                                                                     *
;                                                                     *
;**********************************************************************
;                                                                     *
;    Notes:                                                           *
;                                                                     *
;                                                                     *
;                                                                     *
;                                                                     *
;**********************************************************************


	list		p=16f677	; list directive to define processor
	#include	<p16f677.inc>	; processor specific variable definitions


; '__CONFIG' directive is used to embed configuration data within .asm file.
; The labels following the directive are located in the respective .inc file.
; See respective data sheet for additional information on configuration word.

	__CONFIG    _FCMEN_ON & _IESO_OFF & _BOR_OFF & _CPD_OFF & _CP_OFF & _MCLRE_OFF & _PWRTE_ON & _WDT_OFF & _INTRC_OSC_NOCLKOUT



;***** VARIABLE DEFINITIONS
w_temp		EQU	0x71		; variable used for context saving
status_temp	EQU	0x72		; variable used for context saving
pclath_temp	EQU	0x73		; variable used for context saving


;**********************************************************************
	ORG     0x000             ; processor reset vector

	nop
  	goto    main              ; go to beginning of program


	ORG     0x004             ; interrupt vector location

	movwf   w_temp            ; save off current W register contents
	movf	STATUS,w          ; move status register into W register
	movwf	status_temp       ; save off contents of STATUS register
	movf	PCLATH,w	  ; move pclath register into w register
	movwf	pclath_temp	  ; save off contents of PCLATH register

; isr code can go here or be located as a call subroutine elsewhere

	movf	pclath_temp,w	  ; retrieve copy of PCLATH register
	movwf	PCLATH		  ; restore pre-isr PCLATH register contents
	movf    status_temp,w     ; retrieve copy of STATUS register
	movwf	STATUS            ; restore pre-isr STATUS register contents
	swapf   w_temp,f
	swapf   w_temp,w          ; restore pre-isr W register contents
	retfie                    ; return from interrupt



main

; remaining code goes here




; example of preloading EEPROM locations

	ORG	0x2100
	DE	5, 4, 3, 2, 1

	END                       ; directive 'end of program'

