adctimer.asm

aduc812精典源代码下载,适合初学者

;********************************************************************
;
; Author        : ADI - Apps            www.analog.com/MicroConverter
;
; Date          : 28 May 1999
;
; File          : ADCtimer.asm
;
; Hardware      : ADuC812
;
; Description   : Performs ADC conversions at 10KSPS in Timer2 mode.
;                 Outputs ADC results on P0 & P2.  Continuously
;                 flashes LED (independently of ADC routine) at
;                 approximately 5Hz.
;                 All rate calculations assume 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,#062h   ; power up ADC & enable Timer2 mode
        MOV     ADCCON2,#CHAN   ; select channel to convert
        MOV     RCAP2L,#0D2h    ; sample period = 2 * T2 reload prd
        MOV     RCAP2H,#0FFh    ;   = 2*(10000h-FFD2h)*1.085us
        MOV     TL2,#0D2h       ;   = 2*46*1.085us
        MOV     TH2,#0FFh       ;   = 99.8us

; LAUNCH Timer2 DRIVEN CONVERSIONS...
        SETB	EA              ; enable interrupts
        SETB    EADC            ; enable ADC interrupt
        SETB    TR2             ; run Timer2

; 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 operation is being controlled by Timer2
; and 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