UART swapping on Modem Shell

[Shahin97]

Hello, 

I have two UART AT Command devices attached to by board. One for ESP-AT (compatible = "espressif,esp-at";) and the other is a SIM7080 module (compatible = "simcom,sim7080";). Both are working individually, however having both config parameters enabled, the sim7080 is initiated and the esp-at has this error message:

[00:00:15.040,000] <err> wifi_esp_at: Error registering modem context: -12

However I believe I can only have one UART shell at a time from this post -  Multiple Zephyr Shell instances over UART 

Luckily, I only need one at a time. If the ESP-AT cannot find a Wi-Fi network, switch to GSM on the SIM7080 module. 

I believe I cannot have them initiated in the configurations and have to initiate them in main. How would I go about this? 

The files in question are:

https://github.com/zephyrproject-rtos/zephyr/blob/21b9a1c8239637bbecd0b74381f3d8fb069a47b3/drivers/wifi/esp_at/esp.c#L4

https://github.com/zephyrproject-rtos/zephyr/blob/21b9a1c8239637bbecd0b74381f3d8fb069a47b3/drivers/modem/simcom-sim7080.c#L7

What would I need to call for this to be initiated in main?

[ovrebekk]

Hi

Unfortunately there is no way to uninitialize and initialize drivers in Zephyr, so that you can enable two modules that use the same UART. 

That being said, if you are using the nRF52840 device you should have two UART interfaces available. Could you not assign UART0 to one of the drivers and UART1 to the other?

Best regards
Torbjørn

[Shahin97]

They are on two separate physical UARTs,  however the modem shell only allows one UART for the shell. 

[ovrebekk]

Hi 

Sorry about that, I misread your issue.

I can't find any reference to shell in these drivers, unless it is used by the higher layer protocols, so hopefully the shell limitation should not be relevant. 

Most likely the -12 error originates here, and depends on the size of the MODEM_CONTEXT_MAX_NUM config. Could you try to set CONFIG_MODEM_CONTEXT_MAX_NUM to 2 in your prj.conf file and see if it solves the issue? 

As shown here this configuration will default to 1. 

Best regards
Torbjørn

[Shahin97]

This looks promising, I am currently under a different project, but I will get back on this later this week or next week

[ovrebekk]

Hi 

With some luck it will get you closer to the goal, but it is very common that solving one issue exposes another one
Either way, just let me know when you've had the chance to test it. 

Best regards
Torbjørn