adcpin.asm

aduc812精典源代码下载,适合初学者

;********************************************************************
;
; Author        : ADI - Apps            www.analog.com/MicroConverter
;
; Date          : 15 July 1999
;
; File          : ADCpin.asm
;
; Hardware      : ADuC812
;
; Description   : Performs hardware pin driven ADC conversions and
;                 outputs results on P0 & P2.  Continuously flashes
;                 LED (independently of ADC routine) at approximately
;                 5Hz (assuming an 11.0592MHz Mclk).
;		
;********************************************************************

$MOD812                         ; Use 8052&ADuC812 predefined symbols

LED     EQU     P3.4            ; P3.4 drives red LED on eval board
CHAN    EQU     0               ; convert this ADC input channel..
                                ; ..chan values can be 0 thru 8
;____________________________________________________________________
                                                  ; BEGINNING OF CODE
CSEG

ORG 0000h

        JMP     MAIN            ; jump to main program
;____________________________________________________________________
                                             ; INTERRUPT VECTOR SPACE
ORG 0033H ; (ADC ISR)

        MOV     P0,ADCDATAL     ; ADC result low byte to Port0  
        MOV     P2,ADCDATAH     ; high nibble and channel ID to Port2
        RETI

;====================================================================
                                                       ; MAIN PROGRAM
ORG 004Bh

MAIN:

; PRECONFIGURE...

        MOV     ADCCON1,#064h   ; power up ADC, 6.51us conv+acq time
        MOV     ADCCON2,#CHAN   ; select channel to convert

; LAUNCH CONTINUOUS CONVERSIONS...

        SETB	EA              ; enable interrupts
        SETB    EADC            ; enable ADC interrupt
        ORL     ADCCON1,#001h   ; enable hardware CONVST pin

; CONTINUE WITH OTHER CODE...

AGAIN:  CPL     LED             ; blink (complement) the LED
        CALL    DELAY           ; delay 100ms
        JMP     AGAIN           ; repeat

; the micro is free to continue with other tasks (flashing the LED in
; this case) while the ADC is converting, synchronously to the
; external CONVST pin.  results are being handled by the ADC
; interrupt service routine.

;____________________________________________________________________
                                                         ; SUBROUTINE

DELAY:                          ; delay 100ms

        MOV     R7,#200         ; 200 * 500us = 100ms
DLY1:   MOV     R6,#229         ; 229 * 2.17us = 500us
        DJNZ    R6,$            ; sit here for 500us
        DJNZ    R7,DLY1         ; repeat 200 times (100ms total)
        RET

;____________________________________________________________________

END