FDC2114EVM: Output rate of 2.57ms = 389Hz possible?

Hi Franz,

Can you please clarify the request here ? Is the customer trying to access and control the I2C speed here ? 

The Test Board is operated with Sensing Solutions EVM GUI v1.9.1 . The evaluation is done in single channel mode, and they have set the measurement settings so that the sample time is > 0.625ms. If they now set the sample rate in the window "Data Streaming" the EVM Output Rate will show about 2.57ms =389 Hz. Can this sample rate be set to lower values? 

Hi Franz,

Thanks for getting back. 

I need to look into this more and let you know. I need to get a hold of an EVM and look into this. I will be on vacation next week and will get back to you on around mid-october Meanwhile while I get the info. Do we know what is the sample rate that the customer is looking into ? As in what is the LC design and how fast is the conversion needed for the application ? 

Hi Arjun,

Thank you for looking into this! At the moment they are using the bare EVM without any additional LC-Design. The required sample rate is 2kHz. Can the EVM be set to this frequency via SW only or does HW need to be adapted as well?

Best regards,

Franz

Hi Franz,

The EVM is not designed to support at speed conversion. Its a basic to help customers with the evaluation. for custom development and design a firmware and software needs to be looked at. 

2 Khz seems really low of a frequency. The FDC is driven at 0.1Mhz to 10 Mhz as described in the datasheet. 

If 2 Khz is required consider using the FDC1004. Let me know if this helps! 

Hi Arjun,

The question is just aimed at whether the SW can be set to record data point for graphing at a lower sample rate (2kHz) than what the device provides.

Thank you,

Franz

Hi Franz,

I see what you are asking for. I have added Justin here so he can look at the EVM and provide you the info you need.  

Hello Franz, 

You cannot change the GUI to a faster sample rate than the EVM ouptut rate. If you change the text box to be faster than the output rate, the graph will either just add values as fast as is can (the same rate as the EVM output rate) or the data streaming may not work at all. 

Best Regards, 

Hi Justin,

the customer set the timing through the configuration menu for the EVM. WIth this it should be possible to get to a 2kHz sampling rate (sampling time 0.459 ms), see below.

But unfortunately the output rate doesn't adjust accordingly. It is still at about 2.6 ms. How can this be fixed?

Thank you,

Franz