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Original question:

FDC2114: No interrupt (INTB) on FDC2214 circuit attached

FDC2114: multiple FDC2214 chips on I2C

Jay Lee
Prodigy 10 points
Part Number: FDC2114
Other Parts Discussed in Thread: FDC2214
Hello Texas Instruments，
We are using FDC2214 to detect a capacitive matrix.
For a demo, 4 pcs of FDC2214 chips were used to detect 4*4 capacitive sensors(10pf-300pf).
4 chips were connected to arduino through I2C with high speed 3.4Mbit/s.  We set ADDR pins to Low or High to choose which FDC2214 chip will work. Each chip when selected alone can work well and output right data.
  • 0
    TI__Mastermind 18545 points

    Hello, 

    We don't recommend changing the ADDR pin while the device is not in shutdown mode. When the device wakes up, there is always a delay before the device starts sampling again. Subsequently, each channel has a startup delay when sampling multiple channels. These two effects combined could be why you are seeing the slower sample rate when you have all the channels combined. You could decrease your RCOUNT value or increase your clock to get a better sample rate. 

    Best Regards, 

    Justin Beigel

  • 0 in reply to Justin Beigel
    Prodigy 10 points

    Thank you, Justin.

  • +1 in reply to Jay Lee
    TI__Mastermind 18545 points

    Hello Jay, 

    I do mean decreasing the value of RCOUNT since this will increase the sample rate of the channels. As for the CLOCK_DIVIDERS, you would actually decrease this to increase your reference clock frequency. A faster reference clock can also mean a faster sampling time. 

    Changing the ADDR pin is fine if you control the device by putting it into shutdown first. If you don't want to do this, you could use an I2C mux to communicate with the different devices. 

    Best Regards, 

    Justin Beigel