External AT-interface to the NRF9160

[Clemens]

Hello,

I got the issue to run the NRF9160 DK as an external AT-Modem. What I need to do is to issue AT-Commands over the UART, which control the NRF9160 modem through an external UART interface.

Currently, I have wiped out the NRF52840 and I have compiled and flashed the serial LTE modem example, where I modified the following in proj.config:

CONFIG_UART_2_NRF_UARTE=y
CONFIG_UART_2_NRF_FLOW_CONTROL=n

CONFIG_SLM_GPIO_WAKEUP=n
CONFIG_SLM_CONNECT_UART_2=y

And then the following in .config:

CONFIG_SLM_LOG_LEVEL=4

This allows me to see in the LTE-Link-Monitor the bootup sequence finishing with the lines:

*** Booting Zephyr OS build v2.1.99-ncs1  ***

[00:00:00.193,023] 

[0m<inf> app: Serial LTE Modem

[0m

[00:00:00.193,084]

[0m<dbg> at_host: TX

52 65 61 64 79 0d 0a                             |Ready..          

[0m

[00:00:00.193,725] 

[0m<dbg> at_host.slm_at_host_init: at_host init done

[0m

And I receive a "Ready" signal over the UART_2 through a USB to serial converter connected to P0.10 TXD and P0.11 RXD. 
However, If I send out some AT-Command through the USB to serial converter, I do not get any response from the modem. 
I tried "AT+CFUN?\r\n" as well as "AT+CFUN=1\r\n". Both without any reaction. Do I need to set anything further?

Thank you very much!
Best Regards,

Clemens

[Heidi]

Hi!

Did you make sure to switch the GPIO output level on the nRF91 (SW11) to be 3V?

 

Currently, I have wiped out the NRF52840 and I have compiled and flashed the serial LTE modem example

 This sentence confuses me - is this the nRF52840 on the nRF9160 DK? Or a separate nRF52840 device? And you flashed the SLM sample to the nF9160 SiP correct? 

Best regards,

Heidi