Page 161 - Making PIC Microcontroller Instruments and Controllers

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to simulate back pack
:::P.fi0iittllgitl:tl For a PIC 15F84A (Prosram
lby rnicroEngineering Labsl)
; PicBasic Pro program to sinulate an LCD Backpack
; Define LcD registers and bits
DEFIIiIE LCD-DREG PORfD
DEFIIIE IJCD DBIT 4 j
DEFINE IJCD RSREG PORTE ;
DEFINE LCD_RSBIT O ;
DEFINE I,CD EREG PORTE
DEFINE I.CD_EBIT 1 ;
CI|AR VlrR BYTE ; Storaqe for serial cha.acter
MODE vaR BYTE ; Storage for seriaL node
Rcv vAR PoRl[B.? ; sexia] receive Pin
BAUD VAR PORTA.o r Barrd raLe pin 0 = 2400, 1 = 9600
STATE vAR POR!A,1 ; InverLed or lrue serial data 1 = true

a.DcoNl = %00000111 , set PoRTA and PoRTE to digital
l,Olf PORTE.2 , l,CD R/w line 1ow (i'l)
PAUSE 500 ; i/ait for LCD to slarLup

MODE = 0 ; Set node
IF (BAUD == t) TEEN
MoDE = 2 ; set baud rate
ENDIF

IF (STATE == 0) IHEN
MODE = MODE + 4 ; Set invelled or true
ENDIF

r,cDout $FE, L i Initialize and clear displav

LOOP,
SERIN RC{/, MODE, CEAR ; Get a char fron serial input
LCDOUT CEAR ; Send char to display
GOIO IOOP , Do rt all over again
END ; end Progran

This program is for the 16F8,1A, but it can be used on the 16F877Awith appropriate
DEFINES. You have settheseDEFINES many times before now, so lhis should not be
a problem.
The preceding proFam is for a 16F84A PIC. tf you load this pro$am into the PIC,
you can connect the 16F84A to the LCD, dnd any serial information that comes in on
PORTB.T willbe displayed on the LCD. Now you can conlrol the LCD from one line
on the main processor (The selected pin does nol have to be PORTB.7. Any tree pin
can be specified as the input data pin in the pfogram.)
The wiring diagram for the 16F84A is shown in Figure 9.2.