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FDC1004EVM: FDC1004EVM

Part Number: FDC1004EVM

Hello there,

I am trying to read the capacitance of basic parallel plate capacitor, the capacitance between ground plate and sensor plate. It is actually a micro-structure and the gap between the ground and sensor plates changes. And this capacitive sensor is connected to FDC1004 EVM by about 1 m long coaxial cable. There are two major issues with my sensor application. Hope you give me great comments.

1) How to remove or minimize parasitic capacitance appearing in a dynamic environment? For example, when my finger touches the coaxial cable connecting the EVM and my sensor, the capacitance read by the FDC1004 EVM is changed. 

2) Is it available to collect all the data points mentioned in the company datasheets (400 samples/s, 200 samples/s, and 100 samples/s)? I realized that the software working with FDC1004 EVM does not take all of the data., for example by the 400 samples/s mode, it collects only about 60 data points. Something it collects different number, not 60 points.  If it is possible, how to collect all the data points?

It is said that if this firmware "Capacitive Sensing Sample Code (Energia) v1.1 (Rev. A)" is written to the FDC1004EVM, it is available. And it must be compiled and can then be uploaded to an MSP430. However, it is a little bit hard to catch up.

Can it the code "Capacitive Sensing Sample Code (Energia) v1.1 (Rev. A)" be written to the FDC1004EVM through the GUI software, for the FDC1004EVM is composed of I2C converter based on MSP430F5528 micro-controller and FDC1004? It seems that the company website does not provide a user guide for the code.

Can you give me your comments about my questions? Your comments will be great. Thanks.

TB

  • Would you please give me your great comment  especially on the second question (collecting and controlling data points)? 

  • Hi Tae,

    1. The best way to shield your coaxial cable is to connect the SHLD pin from the FD1004 to the shielding of your cable. This will allow the parasitic capacitances to be between SHLD and ground instead of CINx and ground, which will protect your measurement.

    2. The Capacitive Sensing Sample Code is completely separate from the Sensing Solutions GUI. In order to use the sample code as is, you will need to purchase an MSP430F5529 Launchpad from the ti.com. Then you can follow the instructions in the Getting Started Guide included with the sample code to correctly connect the hardware and flash the MSP430. You can find it in Windows (C):\ti\Capacitive Sensing Microcontroller (Energia)-1.1
    If you do not wish to purchase the Launchpad, the example code can serve as guidelines for how to write your own firmware.

    The sample rate can be configured using the FDC Configuration Register, which should be done in firmware for your MCU. If you want live data from the FDC1004EVM, you will need to write your own program to read data from the FDC1004 (through the MCU) at the sample rate you desire. 


    Regards,

    Kristin Jones

    Sensor Signal Conditioning

    Applications Engineering

  • In reply to Kristin Jones93:

    Hi Kristin,

    Is it "MSP-EXP430F5529LP" the one you are suggesting?

    Best,

    Tae

  • In reply to Tae Hur:

    Hi Tae,

    Yes, that is the correct Launchpad.

    Regards,

    Kristin Jones

    Sensor Signal Conditioning

    Applications Engineering