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FDC2212:About the use of INTB pin in FDC2212

Part Number: FDC2212
Other Parts Discussed in Thread: FDC2114EVM

HI

I am using FDC2212. I want to trigger the MCU via the INTB pin interrupt and read the data register of the FDC2212 via I2C. When initializing the FDC2212, set the ERROR_CONFIG register to 0x0001; the CONFIG register is set to 0x1601. After setting, is the INTB pin output when the data of channel 0 and 1 is ready? If there is? time? INTB pin level? INTB pin output voltage size? if there is not? How to set up registration?

BestRegards

Sun

  • I played with the intB pin... When it is set up as a interrupt, it appears to be momentary. I have not measured the duration the intB pin is held high, but I know for certain that it does not stay high indefinitely. The data sheet suggests that the intB pin is reset by reading data or the status register... It makes no mention of the fact that intB is asserted  momentarily. This is not a problem if you are using it as a "real" interrupt. The bigger issue is when you are polling it... If you are too slow polling (which can happen when debugging or whatever) and you miss intB going high, once it returns low it will never go high again unless you read the register... Long story short, if you don't have a real interrupt routine, then you are better off reading the register.

  • Hi All,

    The INTB pin, when reporting DRDY, operates as shown in the attached image:

    The INTB Maximum Vol with 3mA sink is 0.4V. The Voh > 2.4V.

    Regards,

    ChrisO

  • 1.I saw from the figure above, when the data of channel 0,1 are ready, the level of INTB pin changes, but not my understanding, when the data is ready, INTB pin sends out a high level, Reset after reading. is it?
    2.Then I would like to ask: Can INTB signal be used as external interrupt source signal to trigger MCU?
    3.I follow the manual snoscz9.pdf section 7.3.4 to configure the INTB pin, but the INTB pin is not output, what is the reason?
  • HI

    Manual snoscz9.pdf Section 7.3.4 has the following contents:(The INTB function must be enabled by setting CONFIG.INTB_DIS to 0 Setting register CONFIG.INTB_DIS to b1 disables the INTB function and holds the INTB pin high.)This means that the INTB interrupt is enabled when this bit in the register is set to 0, but I can not use the INTB interrupt in this way. When I tried to set this bit to 1, the INTB interrupt was enabled, and why?

    There are two problems now:

    1.After the first data conversion is completed, only one interrupt occurs, and no interruption occurs after the subsequent data conversion. why?

    2.After reading the conversion data of channels 0 and 1 via I2C, set the FDC2212 to sleep mode and then write 1 to the DRDY_2INT bit of the ERROR_CONFIG register. When the FDC2212 is set to normal mode, an interrupt is generated but the read conversion data is all 0.

     

  • Hello,

    When the INTB pin is asserted, it goes LOW. If the INTB pin is asserted, it will only be deasserted by reading the Status or Data registers, OR putting the device into Sleep mode or Shutdown mode.

    Refer to the application note www.ti.com/.../snoa959.pdf for more information; it also applies to the FDC221x and FDC211x devices.

    Regards,

    ChrisO
  • Hello,

    Do you have the FDC2212 capacitive sensor application source code? I need to refer to your source code! Please tell me the source code link.

    Regards

     

  • Hello,

    Are you asking for the FDC2114EVM firmware? Can you clarify what you exactly need?

    Regards,

    ChrisO
  • I haven't heard back from you for a while, so I'm going to close this thread. If you need any additional help, please post a new thread.

    Regards,
    ChrisO