Sierra Wireless Models Utility Script

Interact with Sierra Wireless modems, specifically AirPrime EM74xx/MC74xx models, using AT commands.

Under development, until then, here's additional instructions.

Modems Tested

• MC7455

MC7455 USB Interfaces

• /dev/ttyUSB2 - NMEA (send $GPS_START/$GPS_STOP to toggle output)
• /dev/ttyUSB3 - AT (see commands in references)

Auto-start GPS without a SIM card

1. Stop and disable ModemManager to prevent conflicts:
   sudo systemctl stop ModemManager && sudo systemctl disable ModemManager

2. Start ModemManager in debug mode to monitor responses:
   sudo /usr/sbin/ModemManager --debug

3. Send the following commands - adjust the index as required, wait for an OK after each command:

   • minicom can also be used to send the commands.

   sudo mmcli -m 0 --command='AT!ENTERCND="A710"'
   sudo mmcli -m 0 --command='AT!GPSAUTOSTART=1,1,255,100,1'
   sudo mmcli -m 0 --command='AT!GPSNMEACONFIG=1,1'
   sudo mmcli -m 0 --command='AT+WANT=1'
   sudo mmcli -m 0 --command='AT!CUSTOM="GPSSEL",0'
   sudo mmcli -m 0 --command='AT!CUSTOM="GPSLPM",0'
   sudo mmcli -m 0 --command='AT!RESET'

Command breakdown

• AT!ENTERCND="A710" - Enable access to password-protected commands
  • A710 is the default code for MC7455 (maybe others)
• AT!GPSAUTOSTART=1,1,255,100,1 - Configure GPS auto-start
  • Enable at boot
  • Standalone fix (no MS assistance, use GPS only)
  • Max time to wait for fix (255 secs)
  • Accuracy of fix (within 100 meters)
  • Time between fixes (1 sec)
• AT!GPSNMEACONFIG=1,1 - Configure NMEA sentences
  • Enable NMEA data output
  • Output rate of 1 sec
• AT+WANT=1 - Enable antenna power (3.3V) for active GPS antennae
• AT!CUSTOM="GPSSEL",0 - Ensure dedicated GPS antenna port is used (default)
• AT!CUSTOM="GPSLPM",0 - GPS remains enabled when modem enters low power mode (e.g, no SIM)
• AT!RESET - Reset modem to apply new configuration

GPSD Setup

• This should be done after the auto-start configuration is applied.

1. Add the modem GPS to gpsd:
   sudo gpsdctl add /dev/ttyUSB2
2. Start the modem GPS output:
   echo -e "\$GPS_START" | sudo tee /dev/ttyUSB2
3. If needed, to stop the GPS output:
   echo -e "\$GPS_STOP" | sudo tee /dev/ttyUSB2

Firmware Upgrade

Reference: Software Integration and Development Guide for Linux

Flash Tool Download

1. Download the Sierra Wireless's Mobile Broadband Package SDK Lite for Linux:
   • MBPL_SDK_Rxx_ENGx-lite.bin.tar
2. Extract the lite-fw-download tool specifically - adapt for your platform:
   tar --extract --strip-components 3 --file MBPL_SDK_R42_ENG4-lite.bin.tar.gz SampleApps/fw-download-tool/bin/fw-download-toolhostx86_64

Firmware Flashing

1. Stop and disable ModemManager to prevent conflicts:
   sudo systemctl stop ModemManager && sudo systemctl disable ModemManager
2. Reboot (may be optional)
3. Download your modem's approved firwmare package:
   • EM/MC74xx
4. Extract the files in an images directory:
   unzip SWI9X30C_02.39.00.00_GENERIC_002.085_000.zip -d images/
5. Run the tool as superuser, the simple one meets requirements - this may take a while:
   sudo ./fw-download-toolhostx86_64 -f images/
6. Monitor the progress by tailing the log file:
   tail -f fwdwl.log
7. Confirm firmware version using minicom:
   1. Send the command AT+GMR, the response should be:
      SWI9X30C_02.39.00.00 rF194F7CA76D79E jenkins 2024/06/05 05:36:47
8. Start and enable ModemManager - if needed:
   sudo systemctl start ModemManager && sudo systemctl enable ModemManager

Development Notes

minicom

1. Install minicom for serial interactions:
   sudo apt install minicom
2. Configure minicom on first run, or if serial port changes:
   1. sudo minicom -s
   2. Use the down-arrow key to go to Serial port setup
   3. Type a to change the Serial Device to /dev/ttyUSB3 - or whatever your AT file handle is
   4. Return to the main menu and go to Screen and keyboard
   5. Type q to enable Local echo so you can see what you're typing!
   6. Return to the main menu and save your config as default by selecting Save setup as dfl
   7. Exit by selecting Exit from Minicom

• To quit minicom, the hotkey sequence is ctrl-a > q > Enter

Monitoring Serial Messages

1. Stop ModemManager:
   sudo systemctl stop ModemManager
2. Start ModemManager in debug:
   sudo /usr/sbin/ModemManager --debug

Credit

• Thanks to Daniel Wood's sierra-wireless-modems project for references and a great start point.