Posts by a_px

    Hi, thanks for the reply. The reason is I am intending to use this in a vehicle application and the vehicle voltage is likely to vary from 11 to 17 volts. With similar applications I have used vehicle laptop supplies to stabilize the voltage, but in general these have an output range of 15-21v. I will try to find a 12v device.



    Hi, is it possible to address the onboard piezo buzzer on a APU4D4 from within the OS? Alternatively, are there any GPIO pins that could be used to add an external piezo buzzer?



    I am attempting to enable 3 x mPCIe LTE modems using a APU4D4 board running Ubuntu 20.04.

    I am aware the SIM slots relate to mPCI slots 2 and 3. I have fitted a SIM carrier to one of the LTE modems in slot 1 and this appears to work. The modem in slot 2 also works and I can query the devices via the USB serial ports that appear in /dev

    However, although the activity LED lights up for the modem in slot 3, I do not see any USB serial ports appearing in /dev for this device and so cannot connect to it. Swapping the modems results in the same issue with no connectivity to the device in slot 3. If I remove the device in slot 3 and place it in an external USB carrier plugged into one of the external USB ports, I can then get all 3 devices to work.

    Is there something I need to do with this slot position (3) in order to enable mPCI functionality as opposed to mSATA? The modem is powered and operating but I don't get any USB connectivity with it when it's in this slot.

    1) The operating system is installed on the SD card, so I don’t need SATA/mSATA

    2) The modems are Simcom SIM7600G-H (1e0e:9001)

    3) The Qualcomm Option driver is installed for these modems

    Thanks Alan