Lopy - Bug with USB



  • i have 2 LoPy's: one of them has been successfully firmware-updated via USB/pycomBoard
    the second LoPy seems to have a bug when connected via USB on the PycomBoard.

    About this 'bad' Lopy:

    • Operational when connected on PycomBoard and powered on with Battery,
    • Not operational when connected on PycomBoard and powered with USB<--PC,
    • Operational when connected on PyComboard powered first with battery and after connected with USB<--PC

    By operational: can be accessed via telnet
    Because the 'good' LoPy does not have any problem with USB/pycomBoard, i assume that nor USB nor PyComboard have bugs.

    I did monitoring with Putty on dev/ttyUSB0 - serial 115200,
    When doing GND-P23 + reset: 99% i do not have information on Putty screen.
    Once i did received: rst:0X01(POWEON-RESET,boot:0X23(DOWNLOAD-BOOT(UART0, UART1.....)) waiting for download. At this
    point, i have tried to do the firmware update but i ended with a failure message: "device reports readiness to read but returned no data.
    Usually i do not receive this message(rst:0X01...) and when i try to do the firmware update i do have the message
    Exception: Failed to connect to ESP32: Timed out waiting for packet header.



  • The problem has been solutionned in a veryy good way. Thanks to Daniel/Abilio for their actions !



  • ... It sounds in a very good way to be solutionned ...
    I



  • Conclusion: Bug on this Lopy.
    Solution proposed by Pycom: return the defective LopY and send a brand new one...
    Great.... But still waiting for the new one.....
    ... questionning....



  • Just some tests results:

    ********** LoPy with a possibly bug ***

    root@debian:/home# dmesg | grep tty
    [ 0.000000] console [tty0] enabled
    [ 1.995111] systemd[1]: Starting system-getty.slice.
    [ 1.995167] systemd[1]: Created slice system-getty.slice.
    [ 76.494314] usb 1-1: FTDI USB Serial Device converter now attached to ttyUSB0

    root@debian:/# setserial -g /dev/ttyS[0123]
    /dev/ttyS0, UART: unknown, Port: 0x03f8, IRQ: 4
    /dev/ttyS1, UART: unknown, Port: 0x02f8, IRQ: 3
    /dev/ttyS2, UART: unknown, Port: 0x03e8, IRQ: 4
    /dev/ttyS3, UART: unknown, Port: 0x02e8, IRQ: 3

    root@debian:/# setserial -g /dev/ttyUSB0
    /dev/ttyUSB0, UART: unknown, Port: 0x0000, IRQ: 0, Flags: low_latency

    Those output done after pluging (LoPy+3.7battery)+USB

    looks like UART failure ?

    ********************************************************$

    ********** LoPy with No possibly bug ***

    oot@debian:/# dmesg | grep tty
    [ 0.000000] console [tty0] enabled
    [ 1.995111] systemd[1]: Starting system-getty.slice.
    [ 1.995167] systemd[1]: Created slice system-getty.slice.
    [ 76.494314] usb 1-1: FTDI USB Serial Device converter now attached to ttyUSB0
    [ 609.752590] ftdi_sio ttyUSB0: FTDI USB Serial Device converter now disconnected from ttyUSB0
    [ 641.645409] usb 1-1: FTDI USB Serial Device converter now attached to ttyUSB0

    oot@debian:/# setserial -g /dev/ttyS[0123]
    /dev/ttyS0, UART: unknown, Port: 0x03f8, IRQ: 4
    /dev/ttyS1, UART: unknown, Port: 0x02f8, IRQ: 3
    /dev/ttyS2, UART: unknown, Port: 0x03e8, IRQ: 4
    /dev/ttyS3, UART: unknown, Port: 0x02e8, IRQ: 3
    root@debian:/# setserial -g /dev/ttyUSB0
    /dev/ttyUSB0, UART: unknown, Port: 0x0000, IRQ: 0, Flags: low_latency
    root@debian:/#



  • Sounds like an issue with the expansion board. Out of the ten I and a friend ordered, one had a solder bridge that shorted out the power supply; it was minuscule and could be removed just poking at it, but means the LoPy wouldn't run. A more common issue is a jumper for the serial connection going missing; the first two, Rx and Tx, are required, while the CTS/RTS ones are normally unused, in case you need to move one. It can be a bit tricky to inspect the boards.


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