Hello:
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I had downloaded a Sing Channel A/D source code from www.michip.com .=20
I made a changed to the List P=3D16c72 to P=3D16C765.
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my question is how do I interpret the result? if I put a 2VDC into =
Pin2(RA0) should I get some reading from PortB?
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Thanks in Advance
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Rith
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;TITLE   "Single channel A/D (SAD)"
;This program is a simple implementation of the PIC16C71's
;A/D. 1 Channel is selected (CH0).
;The A/D is configured as follows:
;       Vref =3D +5V internal.
;       A/D Osc. =3D  internal RC
;       A/D Channel =3D CH0
;Hardware for this program is the PICDEMO board.
;
;
;       Program:          SAD.ASM=20
;       Revision Date:  =20
;                         1-14-97      Compatibility with MPASMWIN 1.40
;
;
 LIST P=3D16C765
        ERRORLEVEL  -302
;
 include "p16c71.inc"
;
TEMP    EQU     10h
adif     equ     1
adgo     equ     2
;
 ORG     0x00
;
;
 goto     start
;
 org      0x04
 goto     service_int      ;interrupt vector
;
;
 org      0x10
start
 movlw    B'00000000'     ;set port b as
 movwf    PORTB          ;all outputs
; tris     PORTB          ;       /
        BSF      STATUS, RP0     ; Bank1
        MOVWF   TRISB           ; PortB as outputs
        BCF      STATUS, RP0     ; Bank0
;
 call     InitializeAD  =20
update     =20
 movf     ADRES,W         ;get a/d value
 movwf    PORTB          ;output to port b
 call     SetupDelay      ;setup time >=3D 10uS.
 bcf      ADCON0,adif     ;clear int flag
 bsf      ADCON0,adgo     ;start new conversion
loop
 btfsc    ADCON0,adif     ;a/d done?
 goto     update          ;yes then update new value.
 goto     loop            ;no then keep checking
;
;no interrupts are enabled, so if the program ever reaches here,
;it should be returned with the global interrupts disabled.
service_int
 return                  ;do not enable global.
;
;
;
;InitializeAD, initializes and sets up the A/D hardware.
;Select ch0 to ch3 as analog inputs, fosc/2 and read ch3.
;
InitializeAD
 bsf      STATUS,5        ;select pg1
 movlw    B'00000000'     ;select ch0-ch3...
 movwf    ADCON1          ;as analog inputs
 bcf      STATUS,5        ;select pg0
 movlw    B'11000001'     ;select:RC,ch0..
 movwf    ADCON0          ;turn on A/D.
 clrf     ADRES           ;clr result reg.
 return
;
;This routine is a software delay of 10uS for the a/d setup.
;At 4Mhz clock, the loop takes 3uS, so initialize TEMp with
;a value of 3 to give 9uS, plus the move etc should result in
;a total time of > 10uS.
SetupDelay
 movlw   .3
 movwf   TEMP
SD
 decfsz   TEMP, F
 goto     SD
 return

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