NRF52833 Adding UART to Thead MQTTSN client publisher

[BBI]

Good day

I need to add UART to a project based "Thead MQTTSN client publisher" example code. The device needs to receive data over UART and then send the data to the MQTT broker. I have tried to port the code over from the peripheral UART example from the same SDK, but to no avail. Where as most of the SDK's examples perfectly illustrate their concept, it can sometimes be a nightmare to merge two examples.

Could you please provide some guidance on how to add UART capabilities to the Thread example.

Project is being done on a NRF52833 chip with version 4.1 of the Thread SDK.

Kind regards

[Jørgen Holmefjord]

There are a couple of things needed to make the project compile:

In sdk_config.h, set NRFX_UARTE0_ENABLED:

// <o> NRFX_UARTE0_ENABLED - Enable UARTE0 instance
#ifndef NRFX_UARTE0_ENABLED
#define NRFX_UARTE0_ENABLED 1
#endif

In project options, remove the preprocessor symbol "UART_ENABLED=0".

Add "#include "bsp.h"" to main.c, before the check for #if defined(UART_PRESENT)\#if defined(UARTE_PRESENT).

I also get one additional error related to the scatter file, but this might be an issue on my end and likely not related to the addition of UART.

[BBI]

Thank you. I'm getting a new error now:
Symbol UARTE0_UART0_IRQHandler multiply defined (by uart.o and nrfx_prs.o)

[Jørgen Holmefjord]

Did you try my previous suggestion?

Jørgen Holmefjord said:

If you want to use UART0 in your application, you may try replacing the library "libopenthread-nrf52833-transport.a" with "libopenthread-nrf52833-transport-none.a

[BBI]

I've changed the libraries, but no luck. I get 6 new errors now.

add_uart_to_threading_2.zip

[Jørgen Holmefjord]

The first 3 errors is because you have not enabled app_uart in your sdk_config.h file:

// <e> APP_UART_ENABLED - app_uart - UART driver
//==========================================================
#ifndef APP_UART_ENABLED
#define APP_UART_ENABLED 1
#endif
// <o> APP_UART_DRIVER_INSTANCE  - UART instance used
 
// <0=> 0 

#ifndef APP_UART_DRIVER_INSTANCE
#define APP_UART_DRIVER_INSTANCE 0
#endif

// </e>

The last 3 errors seems to be because the thread_utils.c file calls otCliUartInit(), which is not implemented after you changed the transport library file. If you comment out that function call, the application should compile successfully. The CLI would anyway not be available without the transport.

[BBI]

The last three errors have been resolved. The first four are still there. Could you please have a look at the program again.
add_uart_to_threading_3.zip
Undefined symbol app_fifo_flush (referred from app_uart_fifo.o)
Undefined symbol app_fifo_get   (referred from app_uart_fifo.o)
Undefined symbol app_fifo_init  (referred from app_uart_fifo.o)
Undefined symbol app_fifo_put   (referred from app_uart_fifo.o)