;******************************************************************************
; This file is a basic template for assembly code for a PIC18F4331. 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 PIC18F2331/2431/4331/4431 Data Sheet for additional *
; information on the architecture and instruction set. *
; *
;******************************************************************************
; *
; Filename: *
; Date: *
; File Version: *
; *
; Author: *
; Company: *
; *
;******************************************************************************
; *
; Files required: P18F4331.INC *
; *
;******************************************************************************
LIST P=18F4331 ;directive to define processor
#include <P18F4331.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 OSC = LP ;LP
;******************************************************************************
;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.
CBLOCK 0x080
WREG_TEMP ;variable used for context saving
STATUS_TEMP ;variable used for context saving
BSR_TEMP ;variable used for context saving
ENDC
CBLOCK 0x000
EXAMPLE ;example of a variable in access RAM
ENDC
;******************************************************************************
;EEPROM data
; Data to be programmed into the Data EEPROM is defined here
ORG 0xf00000
DE "Test Data",0,1,2,3,4,5
;******************************************************************************
;Reset vector
; This code will start executing when a reset occurs.
ORG 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.
ORG 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.
ORG 0x0018
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
;******************************************************************************
;High priority interrupt routine
; The high priority interrupt code is placed here to avoid conflicting with
; the low priority interrupt vector.
HighInt:
; *** high priority interrupt code goes here ***
retfie FAST
;******************************************************************************
;Start of main program
; The main program code is placed here.
Main:
; *** main code goes here ***
; Program ADC as single-hhot mode , One channel @ RA0 ,
movlw B'00000000'
movwf ADCON0
movlw B'00000000'
movwf ADCON1
movlw B'00011101' ; TAD = Fosc/16 , TACQ = 6TAD
movwf ADCON2
movlw B'00000000' ; Interrupt is generated when each word is written to the buffer , All triggers disabled
movwf ADCON3
movlw B'00000000'
movwf ADCHS ; Group-A = AN0 , Group-B = AN1 , Group-C = AN2 , Group-C = AN3
movlw B'11111110'
movwf ANSEL0 ; Only AN0 is Analog input
movlw B'00000001' ;
movwf ANSEL1
clrf TRISD
bsf ADCON0,0 ; Turn AD ON bit
ADC_Loop:
bsf ADCON0,GO
Wait_ADC
btfsc ADCON0,GO
goto Wait_ADC
movff ADRESH,LATD
nop
bra ADC_Loop
;******************************************************************************
;End of program
END