;******************************************************************************
;   This file is a basic template for assembly code for a PIC18F85J90. Copy   *
;   this file into your project directory and modify or add to it as needed.  *
;                                                                             *
;   The PIC18FXXXX architecture allows two interrupt configurations. This     *
;   template code is written for priority interrupt levels and the IPEN bit   *
;   in the RCON register must be set to enable priority levels. If IPEN is    *
;   left in its default zero state, only the interrupt vector at 0x008 will   *
;   be used and the WREG_TEMP, BSR_TEMP and STATUS_TEMP variables will not    *
;   be needed.                                                                *
;                                                                             *
;   Refer to the MPASM User's Guide for additional information on the         *
;   features of the assembler.                                                *
;                                                                             *
;   Refer to the PIC18FXXJXX Data Sheet for additional                        *
;   information on the architecture and instruction set.                      *
;                                                                             *
;******************************************************************************
;                                                                             *
;    Filename:                                                                *
;    Date:                                                                    *
;    File Version:                                                            *
;                                                                             *
;    Author:                                                                  *
;    Company:                                                                 *
;                                                                             * 
;******************************************************************************
;                                                                             *
;    Files required: P18F85J90.INC                                            *
;                                                                             *
;******************************************************************************

    LIST P=18F85J90, F=INHX32    ;directive to define processor
    #include <P18F85J90.INC>     ;processor specific variable definitions

;******************************************************************************
;Configuration bits
;Microchip has changed the format for defining the configuration bits, please 
;see the .inc file for futher details on notation.  Below are a few examples.



;   Oscillator Selection:
    CONFIG  FOSC = HS            ;HS oscillator


;******************************************************************************
;Variable definitions
; These variables are only needed if low priority interrupts are used. 
; More variables may be needed to store other special function registers used
; in the interrupt routines.

        UDATA

WREG_TEMP   RES 1   ;variable in RAM for context saving 
STATUS_TEMP RES 1   ;variable in RAM for context saving
BSR_TEMP    RES 1   ;variable in RAM for context saving

        UDATA_ACS

EXAMPLE     RES 1   ;example of a variable in access RAM


;******************************************************************************
;Reset vector
; This code will start executing when a reset occurs.

RESET_VECTOR    CODE    0x0000

        goto    Main        ;go to start of main code

;******************************************************************************
;High priority interrupt vector
; This code will start executing when a high priority interrupt occurs or
; when any interrupt occurs if interrupt priorities are not enabled.

HI_INT_VECTOR   CODE    0x0008

        bra HighInt     ;go to high priority interrupt routine

;******************************************************************************
;Low priority interrupt vector and routine
; This code will start executing when a low priority interrupt occurs.
; This code can be removed if low priority interrupts are not used.

LOW_INT_VECTOR  CODE    0x0018

        bra LowInt      ;go to low priority interrupt routine

;******************************************************************************
;High priority interrupt routine
; The high priority interrupt code is placed here to avoid conflicting with


        CODE

HighInt:

;   *** high priority interrupt code goes here ***


        retfie  FAST

;******************************************************************************
;Low priority interrupt routine
; The low priority interrupt code is placed here.
; This code can be removed if low priority interrupts are not used.

LowInt:
        movff   STATUS,STATUS_TEMP  ;save STATUS register
        movff   WREG,WREG_TEMP      ;save working register
        movff   BSR,BSR_TEMP        ;save BSR register

;   *** low priority interrupt code goes here ***


        movff   BSR_TEMP,BSR        ;restore BSR register
        movff   WREG_TEMP,WREG      ;restore working register
        movff   STATUS_TEMP,STATUS  ;restore STATUS register
        retfie

;******************************************************************************
;Start of main program
; The main program code is placed here.

Main:

;   *** main code goes here ***


;******************************************************************************
;End of program

        END
