PIC microcontroller programming basic format typical program structure framework

When creating a source program, first use the pseudo-instruction TITLE to provide the program title, then give a general description of the entire program, and use the list pseudo-instruction LIST to specify the microcontroller model and file output format used, and then use the INCLUDE pseudo-instruction to read the definition file provided in MPASM, such as "P16F84 INC", and then define the commonly used resources in the chip, and then give the basic structure framework of the general program. An example is as follows.

TITLE "This is..."; program title

;Procedure Description

LIST P="16F84"，F=1NHX8M

；

include

－config_RC_Qsc＆_WDT_0FF…

; Resource definition and variable definition

STATE OF THE HORSE 03

FSR EQU 04

PORTA EQUIPMENT 05

PORTB EQU 06

J EQU 01F

K EQU 01E

；…………………

ORG 0000 ；

goto MAIN ; skip the interrupt vector

ORG 0004

goto INTSRV; subroutine entry address

；……………………………………

MAIN

; Start putting the main program from 0005H

call Initports; port initialization

call InitTimers; timer initialization

…

INTSRV ... ;Interrupt service routine area

SVBRTH… ; Subroutine area

END ; program end character

Of course, you can adjust it according to the actual situation when writing the program. The following is an actual program list, which requires writing data 88H into the 20H unit of the internal EEPROM of the PIC16F84, and then reading it out from the 20H unit.

LIST P="16F84"，F=INHX8M

；……………………………

STATUSEQU 03; define register

EEDATA EQU 08

EEADR EQU 09

INTCON EQU 0BH

EECON1 EQU 88H

EECON2 EQU 89H

；…………………………

RD EQU 0 ；Define bit

WR EQU 1

RP0 EQU 5

GIE EQU 7

；…………………………

ORG 0

GOTO WRSTART

；……………………………

ORG 10H

WRSTART ; write operation starts

CLRW; Clear W, make W=0

BCF STATUS, RP0; select BANK0

MOVLW 20H

MOVWF EEADR ; address → EEADR

MOVLW 88H

MOVWF EEDATA; write data →

； AUNT

BSF STATUS，RP0 ；选BANK1

BSF EECON1, 2; Write operation enable

BCF INTCON, GIE ; turn off all interrupts

MOVLW 0X55

MOVWF EECON2；55H→EECON2

MOVLW 0XAA

MOVWF EECON2 ；AAH→EECON2

BSF EECON1, WR; Start write operation

BSF INTCON, GIE; Restore interrupt

RDSTART ；Read operation starts

BCF STATUS，RP0

MOVLW 20H

MOVWF EEADR ; address → EEADR

BSF STATUS，RP0

BSF EECON1, RD; start read operation

BCF STATUS，RP0

MOVF EEDATA, W ; EEPROM

; Data read into W

END