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A question of ADC on PSOC4(CY8C4244LQI-443)

ronniejk

Does Pin 1.7 become unavailable for GPIO use(in my case as a Digital High impedance Input), when you use an ADC in the design? Even if reference is set as Internal 1024mv  in the ADC? Because I can see. I can not detect a High on P1.7 even if the level is 3.0V.

  • Please post an image of how you've configured your PSoC4 and the evaluation PCB you're using (if any).

  • in reply to COMPACT

    I've just kludged up a test project which consists of a Digital Input (on Pin 1.7) to a Digital Output (on Pin 1.6) and the inbuilt ADC was configured to use the internal 1.024V ref without bypass with Analog pin on Pin 2.0 as its single single-ended input.

    It built just fine.

     

    If want to use the SAR ADC with the internal 1.024V ref with bypass or external reference with bypass then you'll have to use Pin 1.7 for the bypass and use a different pin for your digital input.

  • in reply to COMPACT

    This is not an evaluation board but an existing  product designed by me. Which has many other components including other Micro Controllers. PSOC4 is not even the main controller.

    I have configured a 3 channel ADC with 1 differential and 2 single ended channels. And ADC works fine. The PSOC4 used is CY8C4244LQI-443.

     

    No problem in compilation. It is just that after this, I am using P1.7 as a Digital Input but it permanently reads LOW Irrespective of the input and irrespective of whether I configure as Open Drain with external pull down or internal pull down or High Impedance Digital or Strong Drive. I will have to comment substantial amount of code of re-do quite a lot of code for me to check without ADC. Which I can, by creating a dummy project later.

    image

  • in reply to ronniejk

    My test project works just fine with p1.7 both as a direct digital input to a digital output pin and as a digital input to the CPU which is read by the CPU and outputs its state to another digital output pin.

    image

    Pin_DigOut is configured with a resistive pullup and is connected to the Red LED on the Pioneer Kit.

    The Blue LED echoes the state of Pin_DigOut through the CPU using

     

          Pin_Blue_Write(Pin_Digin_Read());

     

    When debugging and the CPU halted, shorting P1.7 to ground turns the Red LED on and off as expected.

    When the CPU is running shorting P1.7 to ground also turns on the Blue LED as expected.