LoPy 1 does not boot

  • I recently got a LoPy with the expansion board and started testing it today. I updated the firmware and wrote some code that worked nicely. But now, after a couple of hours, the LoPy does not start.

    When I connect it to USB the green USB light lits up but there is no blinking blue light. Trying to set it to firmware update mode with GND-G23 jumper also didn't help (not detected by firmware updater).

    Is there any other way to do a hard reset? What could have gone wrong? Is my device defective?

  • @robert-hh thank you, I reinstalled ATOM and checked the jumpers on the expansion board and the problem solved. thank you

  • @jclo13 Do you see not message from the com port? Then the cable may be bad. If you see only the output from the unit, but cannot type, then check the jumpers on the expansion board (if you use one).

  • @robert-hh thank you very much, it worked!!!, I use the telnet connections, in the other hand I am having problems whit the com port, It doesn't connect, when I pushed the reset button it boots but I can´t write anything.

  • @jclo13 If you connect P12 to 3.3v and push reset, boot.py and main.py are not executed on boot. Then you could try to modify boot.py & main.py, or just rename them. The last resort is to erase flash or just the file system, and the updater.py tool allows to do that.

  • @robert-hh, what does the lopy expect to download?, I have a similar problem, well I made a mistake, I was trying to mount the sd and it appears an os.error, so y put the code in the boot.py file and I restarted the lopy, now I cant access, I think there is a booting problem, I tried connecting G23 to GND and pushing reset and appears the message, Is there a way to reset it to the factory default manually?

    rst:0x1 (POWERON_RESET),boot:0x13 (SPI_FAST_FLASH_BOOT)
    ets Jun 8 2016 00:22:57

    rst:0x10 (RTCWDT_RTC_RESET),boot:0x13 (SPI_FAST_FLASH_BOOT)
    configsip: 0, SPIWP:0xee
    mode:DIO, clock div:1
    ho 12 tail 0 room 4
    entry 0x400a05d4
    Traceback (most recent call last):
    File "boot.py", line 8, in <module>
    OSError: the requested operation failed
    Traceback (most recent call last):
    File "main.py", line 8
    SyntaxError: invalid syntax
    MicroPython v1.8.6-849-86da809 on 2018-01-17; LoPy with ESP32
    Type "help()" for more information.

    thank you in advance.

  • @seb Tried different cables but still the same voltages. I am thinking I should send this back to where I bought it.

  • @peterkz

    Have you perhaps changed USB cables or USB ports, its possible that one of these is faulty and not delivering enough current to the module.

  • @robert-hh Weird but I'm back at it not booting properly again after a couple of days. Did not use it since last time.

    Measuring voltages I now get:

    VIn - GND = 5.2V
    3V3 - GND = 1.29V
    RST - GND = 1.3V

    2V missing. Do I have a broken voltage regulator somewhere?

  • @peterkz That looks good. Again, if you connect your device to the terminal (atom), connect G23 to GND, and push reset. Then you shouls see a message like:

    ets Jun  8 2016 00:22:57
    waiting for download

  • @robert-hh Measured voltages seem correct:

    VIn - GND = 5.2V
    3V3 - GND = 3.31V
    RST - GND = 3.29V

    But this is very weird. After measuring I was about to write that the LoPy seems dead but then I see the blue flashing light come on and now it booted! Did not touch it for several minutes and did not change anything?

    Sorry to bother you all. Not sure what changed (metal fragment short?, stuck reset button?)

  • Expansion board echos characters typed when bridging tx/rx without LoPy inserted. Will get voltage meter and check levels later. (thank you for replying to my newbie questions).

  • @peterkz If you pull of the LoPy and connect RX and TX at the jumpers, then everything you type at the Terminal (Atom) on you PC should be echoed. That's a simple test for the expansion board. It confirms that the USB/Serial bridge is working. If you have a voltage meter, check the voltage with the LoPy properly inserted at VIn, 3.3V and RST Pins of (for) the Lopy against GND. It should be about 5V at Vin, 3.3V at the 3.3V Pin and about 3.3V at the RST pin. Then you know that the LoPy is properly powered, the Regulator is working and the Deviec is not held in Reset.

  • @peterkz
    what if you connect only expansion board without lopy?

  • Same result when I power it up through a different USB cable. Maybe the expansion board is broken?

  • To clarify it is the LED marked "USB" on the expansion board that stays green. No LED light on the actual LoPy is lit. All jumpers on the expansion board are in place.0_1520149651861_lopy.jpg

  • @peterkz Yes, as terminal something like that atom thing. If the green LED stays, it means that the device starts the bootloader, but not the python app. Normally I would suggest to try a firmware update, but it seems like the communication via USB is broken. So try another USB cable. That typically would not prevent the firmware to start, but ats least it's worth a try. Also, look at the jumpers on the expansion board.

  • @robert-hh Do you mean a terminal like the one the Atom editor plugin provides? I get no output. The terminal just says "Connecting on /dev/cu.usbserial-DO003A44..." but it does not seem to go through. Reset button does nothing.

  • @peterkz Try to connect the device to a terminal and push the reset button (next to the RGB led). What do you get as output?

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