Odd issues.

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    I am having an odd issue with my BerryGPS-GSM, it has been working fine (for about 4 weeks) but has now started to show an odd issue.

    I started the unit up today (connected to a PI Zero W) after it had not been used for around 8 days, the amber light switched on when the PI was powered up and the red light started to flash.

    However when I sent the AT commands to setup the GPS and route strings through the USB interface both leds went out.

    The “Hologram” command also reported modem could not be found and the “ttyACM*” devices were not in the /dev directory.

    When the PI was rebooted the amber light illuminated for a few seconds before switching off.

    Nether trying a micro-usb otg cable or a different PI and SD-CARD did not resolve the issue, however when plugging the GPS-GSM into a Mac it did startup ok.

    When the GPS-GSM was re-connected to the original PI it started up ok and worked for a few minutes until the PI was rebooted.

    However after leaving it for around 10 minutes powered off, it is now working ok.

    Any ideas why I am seeing this behaviour?

    Thank you in advance.

    Mark Williams

    Hi, it could be a power issue.

    Add max_usb_current=1 to the bottom of /boot/config.txt. This will allow the USB port to provide more power.

    Some questions;
    +Do you have a +2A good quality power supply?
    +Is there anything else other than a keyboard or mouse connect to USB?
    +Does it only happen when you are connected to the cellular network?

    After you have the issue, what does the bottom 20 or so lines of dmesg look like? (paste it here)

    Mark --OzzMaker.com --


    Hi Mark,

    Thank you for your response, I will look at adding the line to config.txt, although the board has behave faultlessly today…

    I have actually being running the PI/BerryGPS-GSM off a FTDI/USB lead and powering the combination through the 5volt header – not USB, although I did try powering the combination of a decent power supply when the Leds went out without success.

    There is nothing else on the USB Bus, although there is a Franklin lighting detector on the IC2 bus, powered of the 3 volt line, as above I am using the serial console for debugging.

    The Leds only went off yesterday when I sent the AT commands to start assisted GPS and route strings through USB.

    Although I have not seen the problem today, the last 20 lines of a dmesg are:

    [   65.368047] usb 1-1: new high-speed USB device number 5 using dwc_otg

    [   65.368487] Indeed it is in host mode hprt0 = 00001101

    [   65.658997] usb 1-1: New USB device found, idVendor=8087, idProduct=07ed, bcdDevice= 1.00

    [   65.659018] usb 1-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0

    [   66.308298] usb 1-1: USB disconnect, device number 5

    [   70.958114] Indeed it is in host mode hprt0 = 00021501

    [   71.167979] usb 1-1: new high-speed USB device number 6 using dwc_otg

    [   71.169959] Indeed it is in host mode hprt0 = 00001101

    [   71.423076] usb 1-1: New USB device found, idVendor=1546, idProduct=1102, bcdDevice=17.30

    [   71.423097] usb 1-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3

    [   71.423106] usb 1-1: Product: u-blox Wireless Module

    [   71.423114] usb 1-1: Manufacturer: u-blox

    [   71.423121] usb 1-1: SerialNumber: ************

    [   71.472485] cdc_acm 1-1:1.0: ttyACM0: USB ACM device

    [   71.500036] cdc_acm 1-1:1.2: ttyACM2: USB ACM device

    [   71.523183] cdc_acm 1-1:1.4: ttyACM3: USB ACM device

    [   71.553459] cdc_acm 1-1:1.6: ttyACM4: USB ACM device

    [   71.579135] cdc_acm 1-1:1.8: ttyACM5: USB ACM device

    [   71.606231] cdc_acm 1-1:1.10: ttyACM6: USB ACM device

    [   71.632810] cdc_acm 1-1:1.12: ttyACM7: USB ACM device

    One thing I have noticed today is that  “hologram modem location/operator” commands are returning coordinates for a different location and operator to what I was seeing before – Is it possible that I was connecting to different mast (due to maintenance) it tipped me over the power budget available from the PI/Serial combination – or is that a red herring!



    Mark Williams

    You may be hitting the limit of the 5v pin. According to this link, it is only 1Amp.

    There may not be enough to power the BerryGPS-IMU… especially when your Pi is busy.

    Try using the USB ports once you have increase the current using the command above

    Mark --OzzMaker.com --


    Hi Mark,

    That makes perfect sense – thank you for your help.

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