Modem unresponsive when plugged in before bootup

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Joined: Mon Jul 10, 2017 10:23 pm

Modem unresponsive when plugged in before bootup

Postby sdr » Tue Jul 25, 2017 12:45 am

I have a modem plugged into a Jetson TK1 via a USB hub that will not respond to serial commands when it is plugged in before Jetson bootup. If I unplug it and plug it back in it it works. Here is my dmesg output:

[ 11.608108] usb 1-3.4: new full-speed USB device number 4 using tegra-xhci
[ 11.621862] usb 1-3.4: New USB device found, idVendor=0483, idProduct=5740
[ 11.621874] usb 1-3.4: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 11.621883] usb 1-3.4: Product: Marvelmind Robotics Dashboard device
[ 11.621891] usb 1-3.4: Manufacturer: Marvelmind Robotics
[ 11.621898] usb 1-3.4: SerialNumber: 00000000050C
[ 11.622183] usb 1-3.4: ep 0x82 - rounding interval to 1024 microframes, ep desc says 2040 microframes

The device appears on port /dev/ttyACM0 but does not respond to any serial commands. The red LED flashes periodically on the modem and all beacons wake up and begin blinking blue LEDs as expected.

If I unplug the modem while the Jetson is on and plug it back in, everything works fine. We are communicating with the modem using a custom c++ script. Am I missing a wake command somewhere or something?

Posts: 118
Joined: Sat Feb 06, 2016 4:03 pm

Re: Modem unresponsive when plugged in before bootup

Postby smoker77 » Sat Jul 29, 2017 4:58 pm

Few weeks ago we found the similar imperfection when dashboard software not detects connected modem after rebooting. Current software release (with firmware V5.63) already includes this issue, but it will be fixed in new release which will be published after few days. In your software, if the modem not replies after booting computer, you should send the command, shown on the attached picture, to the modem more than 3 times. After receiving this command four times, the modem reboots and this solves the issue. You will need to reopen port after this. This workaround will work only in next release, not in 5.63 version. In following updates we will try to find the solution which will not require additional commands from user software.
read_version_cmd.PNG (33.84 KiB) Viewed 1530 times

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