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Mimas V2 UART Working only after flash and not on reconnect

Discussion in 'FPGA Boards' started by analog_digital, May 10, 2017.

  1. analog_digital

    analog_digital New Member

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    Hello everyone. As a student at Tor Vergata University in Rome, I just bought some "mimas v2" cards, and we like this product very much. But now we are facing a problem that we can't solve: it's about the serial port.

    For our application, the serial port at 19200 bps was not enough and we needed to flash the firmware at 115200bps. But now we have a problem: just flashed the file bin the interface works in both directions but if we unplug and reconnect the board, the port only works in transmission (verified with the change of LEDs when we send special characters) But it does not work in reception. So if we flash the bin file on the board another time, the UART works in both directions. (In practice, every time we want to open a serial communication, we have to flash the bin file!)

    ps. If anyone is interested, the project is about the Xilinx SEM library (https://www.xilinx.com/support/documentation/ip_documentation/sem/v3_4/pg036_sem.pdf) regarding soft-error correction. (Soft errors are unintentional changes to the values stored in state elements caused by ionizing radiation).

    Then we will go to irradiate the FPGA (and the board as well) with a neutron beam, if anyone is interested, I can share (absolutely FREE, I love the open science! ♥) the schematics, project files, the results, and everything we have (maybe github?).

    pps. if u need, we can provide help in fixing pic firmware, if the problem is in it.

    Thanks in advance for the help.
     
    Last edited: May 13, 2017
  2. rohith

    rohith Moderator Staff Member

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    Hi analog_digital,

    There might be 2 failure vectors here:
    1. MimasV2 UART is not functioning properly
    2. Design's UART is not functioning properly

    Can you try to make sure it is not the second case, by testing your design with an external USB-Serial Module. So that we can confirm it is the PIC's firmware issue.

    Just to make sure, are you using the factory shipped firmware which supports only 19200 baudrate, or you are using the experimental firmware which supports 115200?

    Thanks!
     
  3. analog_digital

    analog_digital New Member

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    Hi rohith,
    thanks you for your quick reply. We actually use the UART port of a RaspberryPI v2 (we have to do the experiment at a distance of about 30 meters from the pc, we need ethernet connectivity for this we use the raspberry). I attach some images to be clearer:

    [​IMG]

    [​IMG]

    And this is our configuration schematic:

    [​IMG]

    For all that concerns serial communication, we use only the shim provided by xilinx, without any customization.

    About the pic firmware we are using the firmware @ 115200bps. With that @ 19200bps we had many wrong characters, and in any case it was not enough for this project.

    Thanks :)
     
    Last edited: May 11, 2017
  4. analog_digital

    analog_digital New Member

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    Any News? or abandoned?
     
  5. rohith

    rohith Moderator Staff Member

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    Hi analog_digital,

    We were not able to reproduce this issue in our lab. Anyways, it looks like PIC firmware issue.

    I would recommed to you to give this alternate open source firmware for MimasV2 a try: https://github.com/jimmo/numato-mimasv2-pic-firmware and check if same issue persists or not.

    MimasV2 can be put into USB Bootloader mode by shorting "FW UP" Jumper

    Thanks!
     
  6. analog_digital

    analog_digital New Member

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    Thank you for the link. I installed the firmware and:

    - On linux, the two devices /dev/TTYACM0 (bitstream upload) and /dev/TTYACM1 (UART communication) are both shown and working properly, apart from the first 2 characters of the UART port (which instead, with an external device , They are displayed correctly), but this is not a problem, at least for our application.

    - On Windows, only UART for communication is, no COM port for programming :( . I think it's a driver problem, I've tried both Numato drivers and other drivers (FT232D, Microchip), but nothing.

    I believe that overall it is a big step forward. Only the last little step is missing :)

    Any idea to fix the problem on windows?

    However, we are also interested in modifying the pic firmware to use the AN1 and AN2 ports on the board. They are also connected to a header and apparently are unused at the moment ...

    Thanks,

    A.D

    ps. I find this pic project very interesting, I think it should be highlighted somewhere, maybe even a post here on the forum :)
     
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  7. rohith

    rohith Moderator Staff Member

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    Hi analog_digital,

    Great to hear that UART communication works with the open source PIC firmware for MimasV2! That indeed confirms a firmware bug in the factory-shipped MimasV2 PIC firmware. I'll report this issue to our embedded department.

    On linux, both COM ports should be accessible easily. Only Windows creates issues when using composite USB devices (devices having more than one independent USB functions/class). A separate driver/inf is needed in this case to get Windows to list both the serial ports. Unfortunately we don't have any expertise on Windows drivers for composite devices. You might want to search on net for this.

    You can certainly modify the PIC firmware to use AN1 and AN2 ports for analog input. It would be great if you could also get this analog-capable firmware merged upstream with the original project!

    And yeah, we should definitely highlight this project. It brings much more capability to MimasV2 which its users might very much like!

    Thanks,
    Rohit
     

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