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PIC18F2550 - pini si program de start |
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Scris de gigipatrud
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Vineri, 24 Octombrie 2008 07:57 |
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Microcontrolerul scris cu programul de mai jos, alimentat cu +5V la VDD si - la cei doi pini VSS, va genera la pinii marcati ca iesire un semnal de 164KHz. Pinul 1 este intrare, iar pinii 15-1, desi se specifica ca ar fi intrare nu am reusit sa dezactivez total portul USB. 
;******************************************************************************
; This file is a basic template for assembly code for a PIC18F2550. Copy *
; this file into your project directory and modify or add to it as needed. *
; *
; Refer to the MPASM User's Guide for additional information on the *
; features of the assembler. *
; *
; Refer to the PIC18Fx455/x550 Data Sheet for additional *
; information on the architecture and instruction set. *
; *
;******************************************************************************
; *
; Filename: *
; Date: *
; File Version: *
; *
; Author: *
; Company: *
; *
;******************************************************************************
; *
; Files Required: P18F2550.INC *
; *
;******************************************************************************
LIST P=18F2550 ;directive to define processor
#include <P18F2550.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 = INTOSCIO_EC ; Internal oscillator, port function on RA6, EC used by USB
; CONFIG FOSC = INTOSC_EC; Internal oscillator, CLKOUT on RA6, EC used by USB
CONFIG WDT = OFF ; HW Disabled - SW Controlled
CONFIG MCLRE = OFF ; RE3 input pin enabled; MCLR disabled
CONFIG PLLDIV = 1
;******************************************************************************
;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
call init_abce
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.
init_abce
BSF UCFG, UTRDIS
BCF UCON, USBEN
; BSF UCON, SUSPND
; BCF SSPCON1, SSPEN
movlw .0
movwf T1CON
movwf T3CON
clrf PORTA
clrf PORTB
clrf PORTC
clrf PORTE
clrf LATA
clrf LATB
clrf LATC
; clrf LATE
movlw 0Fh
movwf ADCON1
movlw 07h
movwf CMCON
movlw .0
movwf TRISA
movwf TRISB
movlw b'00110000'
movwf TRISC
; BSF TRISE, 3
movlw b'01110010'
movwf OSCCON
return
Main:
movlw .255
movwf PORTA
movwf PORTB
movwf PORTC
nop
nop
movlw .0
movwf PORTA
movwf PORTB
movwf PORTC
goto Main
;******************************************************************************
;End of program
END
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