Page 76 - Making PIC Microcontroller Instruments and Controllers

66 COI{TROIII G THE OUTPUT AIIT' READIIIG THE II{PUT

pins at the J7 servo position control, with
!B|!$a$i5;del use servo on iumper
added tunctions
CI;EAR ; clear menory
DEFINE OSC 4 ; osc speed
DEFINE LCD DREG FORED ; define LCD connections
DEFINE LD-DBIT 4 i
DEFINE ICD_RSREC PORTE
DEFTNE ICD_RSBIT O j
DEFINE I|cD AREG FORIE
DEFINE I,CD_EBIT T i
DEFINE ADC_BITS a ; set nunrber of bits in result
DEFINE ADC CLOCR 3 ; set clock source {3=rc)
DEFINE ADC SAt{Pt tUS 50 ; set sanpling line in uS
TRISA - %11111111 ; set PORTA to all inpu!
ERISD = %00000000 ; set all PORTD lines ro ourpuLs
A,DCONI = %00000111 ; PORTA and PORTE to digriLaf
LOW PORIE,2 ; LCD R/W line Low (W)
A2D_VAlttE VAR BY![E ; creaLe A2D_Value to store resr]li
A2D VALttEl VAR BYTE ; creaLe A2D VaLue to store result
A2D vAlIrE2 VAR BIEE : r 6o-6 A. D,.e -e .o
POS VAR WORD ; servo posilions
CEIiIIERPOS vAR WORD ; centex posiLion
!4AXPOS VAR WOF ; nax position
MINPOS Vl.R 9|ORD ; nin position
POSSTEP vIR BYTE ; step length
PAUSE 500 ; wait -5 second
SERVOI VAR PORTC.I ; alias sexvo pin
AICIN 0, A2D VllJttE ; read channeL 0 to A2D Value
OPTIOTiI_REG = $?F ; enable pORTB pu1l ups
t,ol{ SERVO1 ; servo output low
GOSUB CENIER , center servo
r,cDouE $FE. L ; clears screen onLy
PORTB E 0 ; PORTB lines 1ow !o iead butlons
TRISB = %11111110 j Fndbl- fi. s bJ . or ou
MAINIOOP: ; nain progran loop
; check dy buln pres,d !o nove servo
IF PORTB.4 = 0 THEN GOSUB LEA! ; handle lefL nove
IF PORIB.s = 0 THBII GOSUB CBNFER ; hand]e cenLering
MOREB.5 = 0 THEN GOSUB RIGIIII ; handle right nove
ADCIN 0. AzD_VALUE ; read channel 0 to A2D Value
IDCIN 1, AzD VAITUEL ; read channel 1 to A2D Value 1
A.DCIN 3, A2D VAlUE2 t read channel 2 !o A2D,Value 2
MA,|IOS =2350 -127 + A2D VAIJUE1 ; max position reLationship defned
MINPOS =750 +127-a2D_varuEl ; min posiLion relationship defined
CnITERPOS=PO5-127 + A2D vAI;ttE ; coter posilion reLationship denned
; s arr sprvo p! s6
PAUSEUS POS ; puLse length
SER1IOI = 0 ; end servopulse
LCDOUT gFE, 980, 'POS=". DEC POS-127 + A2D_VALUE . \ \,DEC-
A2D VAIJLE, z \.DEC A2D VAIrtEl,/ '. .DEC POSSIEP.' .;
P A U S E 5 : s - ! . o L p o a - a - a o o L l 5 0 L
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