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PSoC 4 MCU

meal_4620636
New Contributor

Hello,

I have two different MCU's of cypress, CY8C4148AZI-S455 and CY8C4146AZI-S433, dealing with ADC_SAR_Seq.

I have noticed that I connected related ADC Pin to the ground, i.e short circuit, I saw 65535 ADC value on CY8C4148AZI-S455, and 20 ADC Value on CY8C4146AZI-S433 via uart protocol. What is the root-cause of such a difference ? Why am I acquring 65535 ADC value which is out of my range resolution (expecting min value ADC 0 and max value ADC 2047). I have attached top design configuration as below.

Any help would be appreciated.

meal_4620636_1-1617181546024.pngmeal_4620636_2-1617181571914.png

meal_4620636_0-1617181877965.png

41484148

meal_4620636_3-1617182016320.png

 

meal_4620636_4-1617182051312.png

 

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3 Replies
Yugandhar
Moderator
Moderator

Hello,

 

Could you please check with "ADC_SAR_Seq_DieTemp" code example from the PSoC Creator and let us know your observations ?

If possible, please share your project so that we can check at our end.

 

Thanks,

P Yugandhar.

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Vasanth
Moderator
Moderator

Hi,

Could you let me know if your input connections ? Are you grounding the input of the ADC through resistors ? Will you be able to share the analog front end connected to the ADC ?

Best Regards,
Vasanth

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Vasanth
Moderator
Moderator

Hi,

Regarding on part of your question, "I saw 65535 ADC value on CY8C4148AZI-S455". This can happen if there is negative noise in your system.

Vasanth_0-1618985664181.png

See the extract from component datasheet. You can try changing your settings to keep Vref as VDDA/2, and single ended negative input as vref to get complete ADC resolution and see the results again.

Best Regards,
Vasanth

 

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