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Michael-C's avatar
Michael-C
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2 years ago

Nios-II Resets with PIO command

I am developing an application using the Nios-II embedded CPU. It utilizes multiple PIO ports, configured as inputs and outputs. I have one in particular that is being very troublesome. Everytime I write to it, it causes the Nios core to reboot.

It resides, in memory, in the same range as the other PIO registers. Nothing seems to jump out that is different from this register than from the others.

Has anyone seen this and possibly some suggestions as to the cause?

Thank You

Nios Cpu

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    • Michael-C's avatar
      Michael-C
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      2 years ago

      I am using the GPIO between a tri-state and a logic low.

      When a logic low, it is connected to a solid state relay (in essence a forward bias diode with Vf typ 1.2V), tied to +5V. There is a 1.91k ohm resistor in series. Thus the sourcing current when driving a logic low would be 5-1.2/1.91k approx 2mA.

  • wwanalim_intel's avatar
    wwanalim_intel
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    2 years ago

    We also would like to know what will happen if toggle the gpio without connecting the relay.


  • Michael-C's avatar
    Michael-C
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    2 years ago

    I have tested the GPIO with the series resister removed, when tri-state it floats around 0.8V. When it drive a logic low, it sets the voltage to 0.0V

  • wwanalim_intel's avatar
    wwanalim_intel
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    2 years ago

    As we do not receive any response from you on the previous question/reply/answer that we have provided. Please login to ‘https://supporttickets.intel.com’, view details of the desire request, and post a feed/response within the next 15 days to allow me to continue to support you. After 15 days, this thread will be transitioned to community support. The community users will be able to help you on your follow-up questions.


  • Michael-C's avatar
    Michael-C
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    2 years ago

    I created a new case in ""FPGA/PROGRAMMABLE DEVICES" section to see if someone else from a different "group" is able to give some input as to what is happening.