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STM32F373VCT6 SDADC READING PROBLEM

lernd
Associate II
Posted on February 26, 2013 at 10:39

The original post was too long to process during our migration. Please click on the attachment to read the original post.
13 REPLIES 13
Amel NASRI
ST Employee
Posted on February 28, 2013 at 14:16

Hello Ram,

In order to check if really the problem root cause is a kind of ''interference'' between the inputs, would it be possible to configure only input 1 and check if the result remains the same after a reset for example.

If the count doesn't remain the same, probably there is a configuration issue.

Curious to know the results...

Best Regards,

ST.MCU

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lernd
Associate II
Posted on March 02, 2013 at 05:31

Hello sir,

I have already configured only one input  and observed the same problem .code mentioned in first post is for single input only Please go through the SDADC settings

SDADC_Config().

.

Thanks.

Ram

raptorhal2
Lead
Posted on March 04, 2013 at 16:33

Crosstalk can occur if the input impedance (RAIN) is not low. You have a 1 K input impedance that requires a sampling time as stated in Data Sheet Table 66. What sampling time is being used ?

Cheers, Hal

lernd
Associate II
Posted on March 06, 2013 at 07:32

Thanks

Hal

 ,

I have configured sampling time  as 1.5Mhz.and 

Now I have put 10E input impedance replacing 1k..But problem still exits.

Posted on March 06, 2013 at 08:59

How are pins 49 (SDADC ground) and 52 (SDADC VREF+) connected?

JW
lernd
Associate II
Posted on March 13, 2013 at 11:28

Hello JW,

Please see pdf attached for pin 49 and 52 connections.

thanks.

________________

Attachments :

CONTROLLER.pdf : https://st--c.eu10.content.force.com/sfc/dist/version/download/?oid=00Db0000000YtG6&ids=0680X000006I0o3&d=%2Fa%2F0X0000000bdr%2FwOBPfMD7.K1y.TkgYSL3gFXBv77gAg2sUAsRO9EkY94&asPdf=false
Posted on March 13, 2013 at 14:43

That looks OK.

I have no more ideas, sorry...

JW
Amel NASRI
ST Employee
Posted on May 14, 2013 at 18:51

Hello Ram,

Back to this discussion after 2 months!! I hope the issue is already fixed. If not, we can check again. So, In the code, why do you have this sequence:

1.
SDADC_VREFSelect(SDADC_VREF_VREFINT2); 
2.
Delay_SW(1000); 
3.
SDADC_Cmd(SDADC1, ENABLE); 
4.
.... 
5.
SDADC_Cmd(SDADC1, DISABLE); 
6.
.... 
7.
SDADC_Cmd(SDADC1, ENABLE);

I think only the 1st enable is needed. Let me know please. Best Regards, ST.MCU

To give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.

bpacan
Associate II
Posted on July 01, 2013 at 13:56

Hello

I just want to say, that our custom board has similar issue. We are using 8 SDADC single ended channels for resistance measurements and 8 ADC channels for voltage measurements. ADC and SDADC channels share some of analog circuit, but we don't see this problem when voltage is applied. So I assume it comes from inside of STM SDADC.