STM32F373VCT6 SDADC READING PROBLEM

lernd · ‎2013-02-26

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.

Amel NASRI · ‎2013-02-28

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 · ‎2013-03-01

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 · ‎2013-03-04

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 · ‎2013-03-05

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.

waclawek.jan · ‎2013-03-05

Posted on March 06, 2013 at 08:59

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

JW

lernd · ‎2013-03-13

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

waclawek.jan · ‎2013-03-13

Posted on March 13, 2013 at 14:43

That looks OK.

I have no more ideas, sorry...

JW

Amel NASRI · ‎2013-05-14

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

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bpacan · ‎2013-07-01

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.