8-bit MicrocontrollersのトピックProblems with QD2 ADC

Problems with QD2 ADC

Zetta08 — Wed, 18 Feb 2009 04:13:43 GMT

I am using the QD2 and I have problems with the ADC

The instructions for Init_ADC init code are:

LDA #$18
STA SPMSC1

                     LDA     #$F0
                     STA     ADCCFG

MOV #$01,ADCSC1

LDA #$02
STA APCTL1

In de Loop:

                    BSET    ADCSC1_ADCH1,ADCSC1

WAIT TST ADCSC1

                    BPL     WAIT

                    LDA     ADCRL

........................

But ADCRL it is always $00

I need some help
That I am making bad

Re: Problems with QD2 ADC

bigmac — Wed, 18 Feb 2009 08:41:44 GMT

Hello, and welcome to the forum.

I will comment your code, and you can judge whether it meets your intention - I don't believe it does.

Zetta08 wrote:

I am using the QD2 and I have problems with the ADC

The instructions for Init_ADC init code are:

     LDA #$18
     STA SPMSC1

     LDA #$F0
     STA ADCCFG

     MOV #$01,ADCSC1 ; Commence conversion Ch 1

     LDA #$02         ; Select Ch 1 for analog operation
     STA APCTL1

In de Loop:

     BSET ADCSC1_ADCH1,ADCSC1
     ; Abort conversion & commence new conversion Ch 3

WAIT:
     TST ADCSC1
     BPL WAIT         ; Loop until conversion complete

     LDA     ADCRL
     ........................

But ADCRL it is always $00

Regards,
Mac

Re: Problems with QD2 ADC

Zetta08 — Wed, 18 Feb 2009 19:49:56 GMT

Hello Mac

For that say that
BSET ADCSC1_ADCH1,ADCSC1 ;it begins a new conversion in the channel CH3

In the Loop I use the following instructions but it always jumps to HAB_DISPARO

This means that ADCRL is always > #$64 (Not #$00, sorry)

LDA ADCRL

                    CMP     #$64
                      BHS     HAB_DISPARO

INH_DISPARO    BSET    F_NIVEL,CONDICION
                     BRA     FIN_CICLO

HAB_DISPARO BCLR F_NIVEL,CONDICION

..............................

Thank you and regards

Zetta08

Re: Problems with QD2 ADC

bigmac — Fri, 20 Feb 2009 12:20:24 GMT

Hello Zetta08,

I might have expected that your intent was to measure channel 1, rather than channel 3. As you have not selected analog operation for channel 3 (APCTL1 register), it is possible that this input may have its digital pullup enabled, which may account for your observations.

I suggest that you don't use the BSET instruction for initiating a conversion - simultaneously write to all bits of the ADCSC1 register to reduce the confusion over what bits are already set.

MOV #$01,ADCSC1 ; Commence conversion Ch 1

MOV #$03,ADCSC1 ; Commence conversion Ch 3

Regards,

Mac

Re: Problems with QD2 ADC

Zetta08 — Fri, 20 Feb 2009 19:23:57 GMT

Finally I found the solution.

It is necessary to disable the PTA1 before beginning the conversion.

In my case the correct instructions are:

Common initialization of the write once registers

LDA #$F0
STA ADCCFG

; ADCCFG: ADLPC=1,ADIV1=1,ADIV0=1,ADLSMP=1,MODE1=0,MODE0=0,ADICLK1=0,ADICLK0=0

In de loop:

              LDA     #$02                             ; Disable the Port PTA1 as I/O
              STA     APCTL1
              MOV     #$01,ADCSC1                ; It begins the convertion

; Or: BSET ADCSC1_ADCH1,ADCSC1

WAIT       TST     ADCSC1                        ; Waits to that finishes the conversion
              BPL     WAIT

              LDA     ADCRL

. . . . . . . . . . .

It works correctly

Thanks to all and greetings