GSM Modem Driver Initialization Question

Hi. I've been working on getting a gsm modem functional using the GSM Modem Zephyr driver on an nRF5340. I believe I have the overlay file setup correctly, but am recieving unexpected log output. There is log output for net & ppp configuration before any code in main is called to initialize the modem, as per the sample gsm_modem. The modem is on UART1 and the output is going to the console on UART0, as best as I can tell. 

The first 2 log lines show different address for the gsm modem than what device_get_binding("modem_gsm") returns.I'm currently blocked at an error message from gsm_ppp.c in gsm_configure() that sends "AT" to the modem and expects "AT" back. Origin or last log error message: gsm_ppp.c #L975.

Should I be concerned with the different device addresses or not?

  • net_ppp.ppp_driver_init: 0x20000214
  • modem_gsm.gsmo_init: Generic GSM Modem: 0x20000730
  • main() gsm device: 0x2000025c

.

Based on other overlay files on github I believe I have the overlay file correct.

Edit: Modem: NL-SW-LTE-TC4NAG

I'm using Pin 3 for TX. Pin 3 can be used for NFC or GPIO. I had to add a config option to prj.conf: `CONFIG_NFCT_PINS_AS_GPIOS=n`.