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FDC2114EVM: FDC2114EVM Sampling Rate

Susan Lane
Prodigy 220 points

Part Number: FDC2114EVM
Other Parts Discussed in Thread: FDC2114

I am trying to plot the change in capacitance using the FDC2114EVM, and the FDC2114EVM GUI, and log this data to an excel file. I purchased this boards because the datasheet says that it can achieve a maximum output rate of 13ksps.

According to the graph configuration tab, the Data Sample Rate can only achieve around 400 sps. Adding samples to the graph at faster rate plots the same data samples more than once, instead of sampling at a faster rate.

I have altered the reference and sample count on the configuration tab, however the data still can only achieve 400 sps, regardless of how I change these two values.

How can I achieve a faster sampling rate?

  • 0
    TI__Genius 17440 points

    Hi Susan,

    While the FDC2114 can achieve a sample rate of 13ksps, the GUI cannot. This is largely to reduce the GUI's graphics processing requirements. You can change the RCOUNT setting so that the FDC2114 on the EVM will sample at a rate of 13ksps and the resolution of the data will be accurate for your desired sample rate, but you cannot increase the GUI's data sample rate. In order to access all of the samples from the FDC2114 you would need to write your own GUI or other program. The FDC2114EVM firmware is included with the Sensing Solutions GUI if you would like to modify it.

    Regards,

  • 0 in reply to Kristin Jones93
    Prodigy 220 points
    From what I've read, the FDC2114EVM has a hard time interfacing with anything other than the TI GUI, and in previous questions I've asked, no one has found a solution to working with the board in LabVIEW, for instance.

    Could you recommend any methods of effectively finding an alternative to the provided GUI?
  • 0 in reply to Susan Lane
    TI__Genius 17440 points
    Hi Susan,

    Unfortunately there is no simple way to do this. If you have access to a logic analyzer, you could modify the EVM firmware so that the MCU polls the FDC device at 13ksps. You could monitor the SDA and SCL lines on the EVM with the logic analyzer and save the data that way. If not, you will likely have to write a program to control the EVM via USB. If you decide to go this route we have some resources available to make the coding easier: dev.ti.com/.../

    If you decide to modify the EVM firmware (found in C:\ti\Sensing Solutions EVM GUI-1.9.4\EVM Firmware), please send me a private message. The GUI download includes the source code, but not the CCS project. I'd be happy to provide you with the CCS project.

    Regards,
  • 0 in reply to Kristin Jones93
    Prodigy 220 points
    Thanks, I think I plan on modifying the firmware. I sent you a private message, hopefully you receive it.