FDC2114EVM: A problem about setting the register of drive current

tian t

Part Number: FDC2114EVM

I'm testing the FDC2114EVM using the EVM GUI. When i set the register of the drive current, I found the frequency changes with the drive current. This is normal? Where is my issue?

I used the singal channel,and control the Vpk between 1.2 to 1.6V. And the settle count and reference count are set with the values from the datasheet because my cap is similar as the example.

over 4 years ago

0 John Miller - Sensing over 4 years ago

TI__Mastermind 40295 points

Tian,

Thank you for the inquiry and your interest in TI products.

You mentioned the frequency changes with the drive current.
How are you measuring the frequency?

Regards,
John

0 tian t over 4 years ago in reply to John Miller - Sensing

Prodigy 10 points

I read the value of the register.It showed me the frequency changing.

0 John Miller - Sensing over 4 years ago in reply to tian t

TI__Mastermind 40295 points

Tian,

A few questions:
Would you please upload the device settings to this thread?
Which channel of the EVM are you using, and which register are you reading?
What are the register & frequency readings?
Would it be possible confirm the register & frequency readings by measuring the sensor frequency with an oscilloscope?

Regards,
John

0 tian t over 4 years ago in reply to John Miller - Sensing

Prodigy 10 points

I just used EVM board and EVM GUI to read the register and frequency. The GUI can auto to detect the board.You mean the GUI may have some problem？I can‘t use it directly？

0 John Miller - Sensing over 4 years ago in reply to tian t

TI__Mastermind 40295 points

tian,

You can use the EVM for what you want to do, but since you are running into problems, I was wondering if something wasn't correct.
Could confirm the frequency reported by the device to the sensor frequency as measured by an oscilloscope?
Is that possible?

If it is not, could you share the non-default device settings so I can try to reproduce your results on my end?

Regards,
John

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FDC2114EVM: A problem about setting the register of drive current