uart_callback_set returns -ENOSYS

Question

I have two projects using different boards. 
 First one (uses attached board = btLTE_nrf52840) works fine. The application are similar in that both make use of the UARTE driver. 
 The second one (uses attached board = w5500_nrf52840) uses the W5500 Ethernet driver. This application works fine except that in the case of the second board, uart_callback_set() returns error - ENOSYS. I have seen other cases reported for the same issue, but I have not been able to determine why this is the case.

I must be something to do with the settings or the board. 
 
 I would appreciate any assistance. 
 
 I include the im 7851.code.zip plementation for both boards, the config settings for working and none working applicayion as well as the 
 common uart code.

Jørgen Holmefjord · Accepted Answer

Hi, 
 The problem is likely that the uart0 instance is used by the NET_SHELL that you have enabled in your prj.conf file. In /build/zephyr/zephyr.dts, we can see: 
 / {
	chosen {
 zephyr,shell-uart = &uart0;
	};
}; 
 You can either disable NET_SHELL in your prj.conf: 
 CONFIG_NET_SHELL=n 
 Or assign it to another uart instance in your board overlay: 
 / {
	chosen {
 zephyr,shell-uart = &uart1;
	};
}; 
 Both these alternatives resolved the error in your test application. 
 Best regards, Jørgen

fgeldenh · Answer

Thank you so much. Saved me a lot of agony.

uart_callback_set returns -ENOSYS

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