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Re: APP001配18F4520的AD無法轉換
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版主
 
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主程式裡沒有看到 AD 啟動轉換的動作?
ADCON0<GO/DONE> 沒有設為 1 , AD 是不換轉換的。
發表於: 2008/3/7 14:19
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APP001配18F4520的AD無法轉換
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新會員
 
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我使用APP001的實驗板~ 搭配18F4520的PIC~
跑教育訓練所提供的程式如下~ 但AD轉換一直無法出來~ 我有查AN0的電壓是確實有變化~ 但PORTA似乎沒辦法進行電壓輸入的工作~ 請問是板子有問題嗎?? ;************************************************************************** ;**** File : Ex3.asm ;**** Read VR1 with the analog voltage input and convert the voltage ;**** to 8-bit digital on LED ;************************************************************************** list p = 18F4520 include <p18F4520.inc> ; C_Hold_Delay equ 0x20 ; ;******************************************************************** ;**** RESET Vector @ 0x0000 ;******************************************************************** org 0x0000 ; bra Main ; org 0x0008 ; bra Hi_ISRs ; ;******************************************************************** ;**** The Main Program start from Here !! ;******************************************************************** org 0x0020 Main: call Init_IO call Init_AD ; AD_Loop call C_Hold_Time ; Delay 50uS for the sample hold time bsf ADCON0,ADON ; Start convert the A/D nop ; Nop btfsc ADCON0,GO ; Check the A/D completed ? bra $-4 ; A/D isn't completed yet, continut check. movff ADRESH,PORTD ; save the a/D result with MSB to PORTD ; goto AD_Loop ;*********************************************************************** ;**** Initial the PORTD for the output port ;*********************************************************************** Init_IO: clrf TRISD clrf PORTD ; bsf TRISA,RA0 ; Set RA0 with input mode ; return ;*********************************************************************** ;**** Initial A/D converter ;*********************************************************************** Init_AD: movlw b'00001110' ; Left Justified, Fosc/32 movwf ADCON1 ; Set AN0 for the Analog Input ; movlw b'10000001' ; Fosc/32 , Select AN0 channel movwf ADCON0 ; A/D on ; bcf PIE1,ADIE ; Disable interrupt of A/D return ; ; ;*********************************************************************** ;**** Sample Hold (Charge) time delay routine (50uS) ;*********************************************************************** C_Hold_Time: movlw .50 movwf C_Hold_Delay nop decfsz C_Hold_Delay,F bra $-4 return ;*************************************************************************************** ;**** ISRs() : High priority interrupt service routine ;**** ;*************************************************************************************** Hi_ISRs retfie FAST ; Return with shadow register ; END
發表於: 2008/3/6 14:33
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