RM520N-GL switch to PCIe mode

Hello,

we have an RM520N-GL module connected to the NVIDIA Jetson Orin NX via its own carrier board. USB mode works fine, but if the module is switched to PCIe mode, it is not detected by the PCIe subsystem - it is not visible in “lspci”.

So, as a first step, I want to check with you that the mode switching process is correct:

  1. Default state: 5G module is in USB mode, 4 serial devices created (/dev/ttyUSB0-3)
  2. Connect via serial terminal to /dev/ttyUSB2
  3. Send command AT+QCFG=“data_interface”,1,0
  4. Make sure the configuration is set correctly: AT+QCFG=“data_interface” → is 1,0
  5. Reset the module via a dedicated pin (or reboot the board, or reset power),

After this, the “lspci” should display the new device (but it doesn’t).

Is this process correct, or am I missing something?

Have you checked the
AT+QCFG="pcie/mode"

It will take effect after reboot.

AT+QCFG=“pcie/mode”

+QCFG: “pcie/mode”,0
OK

AT+QCFG=“data_interface”,1,0

+QCFG: “data_interface”,1,0
OK

I turned the power of the whole system on/off. Is that enough, or do I have to send another command?

Maybe you can provide the dmesg log.

We need to check the power on sequence.
If the modem power on too earlier, it cannot be recoginzed.

It didn’t work because of a bad power-up sequence. Now the module is enumerated using PCIe. Thank you for your time.