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FDC2114: Reading DATAx doesn't de-asserts INTB

Part Number: FDC2114

Hello,

I want to read Data von DATAx just if there is new data available. ERROR_CONFIG[0] is set to 1 and CONFIG[7] is set to 0 that the FDC asserts INTB as soon as new data is available.
The problem is, that INTB does not de-assert when DATAx is read. INTB is held LOW until the STATUS register is read. but normally reading DATAx clears STATUS and therefore INTB should be deasserted. 

The output of STATUS when read is the following: 1100000001000000
This seems pretty normal to me. 

First and Second 1: Flag for Channel 3
Third 1: Data is ready

So where is the problem?

Thanks in advance,
Jonas

  • Hi Jonas,

    The status register must be read to deassert INTB as is documented in the data sheet. Reading any other register will not deassert INTB.

    Best regards,

    Blair
  • Hi Blair,

    thanks for the information. It seems that I misunderstood the following lines (p. 20, Datasheet FDC2114): "When a bit field in the STATUS register is set, the entire STATUS register content is held until read or until the
    DATA_CHx register is read. Reading also de-asserts INTB." 
    To me it sounds like reading DATA_CHx clears STATUS and therefore de-asserts INTB as well.

    But thanks for clarification.

    Best regards,

    Jonas