GE865: Powering ON checks

3 thoughts on “GE865: Powering ON checks

  1. For powering ON the GE865 we use an open-drain buffer on ON_OFF (B1)  and RESET (C1) pins.

     

    The buffer open-drain is TI SN74LVC2G07DCK dual buffer.

     

    We notice some strange results when toggling the buffer input and have the following comments

     

    1. Voltage on pin ON_OFF toggles to 1.15V and 0.4V.

    2. What are the voltagesexpected on the ON_OFF pin?

    3. Datasheet specifies 47K internal pull-up to VRTC pin

    4. We monitor PWRMON pin

     

    We would like to check the two points:

     

    a. Are the open-drain 74LVC2G07 suitable for controlling the GE865 module?

    b. What  are the voltagesexpected on the ON_OFF pin exactly?

        We assumed that the internal pull-up of 47K would give a 2.8V logic level.

     

    1. I would make a simple test, putting in place the circuit described in Hardware User Guide; maybe you have other connections that have influence on observed behavior.

      1. Done. Transistor NPN biased for Reset and ON_OFF implemented.

        No significant differences.

         

        Voltages are 0V and 0.4V when togging the transistors BCR135 with 1V8 from uP.

         

        What are the voltages we should have at the collector please?

        We expect a 2V8 logic – but it does not seem to be the case.

         

        F. Arnaud