帮我看看，ADC程序，执行的有点奇怪

healy_sun

;*******************************************************************
;* This stationery serves as the framework for a user application. *
;* For a more comprehensive program that demonstrates the more     *
;* advanced functionality of this processor, please see the        *
;* demonstration applications, located in the examples             *
;* subdirectory of the "Freescale CodeWarrior for HC08" program    *
;* directory.                                                      *
;*******************************************************************
; Include derivative-specific definitions
            INCLUDE 'derivative.inc'
;
; export symbols
;
            XDEF _Startup
            ABSENTRY _Startup
;
; variable/data section
;
            ORG    RAMStart         ; Insert your data definition here
ExampleVar: DS.B   1
adChannelSel: ds.b 1
adValueChannel0H: ds.b 1
adValueChannel0L: ds.b 1
adValueChannel1H: ds.b 1
adValueChannel1L: ds.b 1
adValueChannel2H: ds.b 1
adValueChannel2L: ds.b 1
adValueChannel3H: ds.b 1
adValueChannel3L: ds.b 1
 
;
; code section
;
;            ORG    ROMStart
_Startup:
            LDHX   #RAMEnd+1        ; initialize the stack pointer
            TXS
            CLI                     ; enable interrupts
           
         lda #$03  ;Disable Copt, Reset,BKBD enanble
         sta SOPT1 
        
         jsr initialAdc         
mainLoop:
            ; Insert your code here
           
            jsr adcTask
            jsr adcIsr
            nop
            nop
                                                                                                                                  
            BRA    mainLoop
;*******************************************************************           
initialAdc:
            ;ADCSC2
            lda #%00000000
            sta ADCSC2
            ;ADCCFG
            lda #%10001000
            sta ADCCFG
           
            ;APCTL1
            lda #$0f
            sta APCTL1
            lda #$00
            sta APCTL2
           
            ;ADCSC1 setting
            lda  #%00000000
            sta  ADCSC1           
           
            lda #$00          ;start form ad channel0 t
            sta adChannelSel
           
initialAdc_end:           
            rts
;*******************************************************************
adcTask:          
            lda adChannelSel
            cmp #$00
            bne adcTaskChannel1Setting
adcTaskChannel0Setting:
            lda #$01
            sta adChannelSel
            jmp adcTaskEnd
adcTaskChannel1Setting:
            cmp #$01           
            bne adcTaskChannel2Setting
           
            lda #$02
            sta adChannelSel
            jmp adcTaskEnd
           
adcTaskChannel2Setting:
            cmp #$02           
            bne adcTaskChannel3Setting
            lda #$03
            sta adChannelSel
            jmp adcTaskEnd 
           
adcTaskChannel3Setting:
            lda #$00          ;start form ad channel0 t
            sta adChannelSel                                           
adcTaskEnd:
            lda  adChannelSel  
            ora  #%00000000
            sta  ADCSC1
        
adcTaskEndAB:           
 ;          lda ADCSC1        
;           and #$80        ;test COCO
;           cmp #$80
            brclr 7,ADCSC1,adcTaskEndAB 
           
                    
            
             rts
;*******************************************************************            
adcIsr:
             lda adChannelSel
             cmp #$00
             bne adcIsrStoreChannel1Value           
adcIsrStoreChannel0Value:
             lda ADCRH
             sta adValueChannel0H
             lda ADCRL            
             sta adValueChannel0L
             jmp adcIsrEnd
            
adcIsrStoreChannel1Value:
            cmp #$01
            bne adcIsrStoreChannel2Value
           
            lda ADCRH
            sta adValueChannel1H
            lda ADCRL            
            sta adValueChannel1L
            jmp adcIsrEnd   
                   
adcIsrStoreChannel2Value:
            cmp #$02  
            bne adcIsrStoreChannel3Value        
            lda ADCRH
            sta adValueChannel2H
            lda ADCRL            
            sta adValueChannel2L
            jmp adcIsrEnd
           
adcIsrStoreChannel3Value:
            cmp #$03
            bne adcIsrEnd
            lda ADCRH
            sta adValueChannel3H
            lda ADCRL            
            sta adValueChannel3L
            jmp adcIsrEnd            
                                     
adcIsrEnd:
            rts
           
;**************************************************************
;* spurious - Spurious Interrupt Service Routine.             *
;*             (unwanted interrupt)                           *
;**************************************************************
;spurious:                           ; placed here so that security value
;           NOP                     ; does not change all the time.
;            RTI
;**************************************************************
;*                 Interrupt Vectors                          *
;**************************************************************
;            org   $ffd0
;            dc.w  adcIsr
;           
;            ORG   $FFFA
;            DC.W  spurious          ;
;            DC.W  spurious          ; SWI
;            DC.W  _Startup          ; Reset
////////////////////////////////////////////////////////////////////////////////////////
其中有几行
adcTaskEnd:
            lda  adChannelSel  
            ora  #%00000000                
            sta  ADCSC1
        
adcTaskEndAB:           
 ;          lda ADCSC1                                                      ---------这行读值，本来是0X81,可是只能读出0x01
;           and #$80        ;test COCO
;           cmp #$80
            brclr 7,ADCSC1,adcTaskEndAB 

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安

说明没有产生AD转换。检测配置或者检测外部输入电压的引脚是否正确。

healy_sun

版主你没理解我的意思
我是说：本来我是这么写的
adcTaskEndAB:           
          lda ADCSC1
          and #$80        ;test COCO
          cmp #$80
          jmp adcTaskEndAB
在debug是，断点打在 and #$80        ;test COCO
然后看A寄存器的值，此时A= 0x81,但是继续单步执行完and #$80
A里的值却不是0x80,导致程序死循环。
于是我把这几行注释掉了，改成brclr 7,ADCSC1,adcTaskEndAB
程序就好了，得到了正常的结果。
所以我想觉得是lda ADCSC1这行是不是执行错了？
问问有人遇到过和我一样的问题，还是我的AD程序那里写的不好，造成这样奇怪的现象？

softradio

adcTaskEndAB:
lda ADCSC1
and #$80 ;test COCO
cmp #$80
jmp adcTaskEndAB
jmp adcTaskEndAB是绝对跳转，前面比了再多也没用。应该用BEQ或者BNE指令。
这种写法只在ADCSC1地址超过0x100的时候才有意义。一般说来绝大多数的ADCSC1都是在0x00~0xFF之间。即使要这样写，也没问题，AND完直接BEQ或者BNE就可以了，CMP本来就是多于。因为AND的操作影响Z位。

healy_sun

恩，4楼说的没错
刚用飞思卡尔的汇编，很不熟悉，
谢谢了