Openthread with FreeRTOS

Question

Hi!
I've successfully set op an OpenThread MQTT broker using a Rasperry Pi and nrf52 dongle and I am able to publish and subscribe to and from my computer by flashing the mqttsn_client_subscriber and mqttsn_client_publisher examples to my nrf52840 DK.

I want to incorporate thread communication into a larger project on the nrf52840 DK using FreeRTOS. My first step has been trying to modify the mqttsn_client_subscriber example to incorporate FreeRTOS. However I have not had much success.

Does the SDK provide examples of OpenThread with FreeRTOS or are there other sources I can consult?

Asgeir · Accepted Answer

static void thread_stack_task(void * arg)
{
 UNUSED_PARAMETER(arg);
 mqttsn_init();
 uint32_t err_code = mqttsn_client_search_gateway(&m_client, SEARCH_GATEWAY_TIMEOUT);
 if (err_code != NRF_SUCCESS)
 {
 NRF_LOG_INFO("SEARCH GATEWAY message could not be sent. Error: 0x%x
", err_code);
 }else{
 NRF_LOG_INFO("Search gateway message sendt");
 }

 while (1)
 {
 NRF_LOG_INFO("in loop");
 
 thread_process();
 app_sched_execute();
 if (NRF_LOG_PROCESS() == false)
 {
 thread_sleep();
 }

 UNUSED_VARIABLE(ulTaskNotifyTake(pdTRUE, portMAX_DELAY));
 }
}
 
 Thank you for the reply! Moving the mqttsn_init() function and code for connecting the gateway into the task, i.e. running it after the vTaskStartScheduler(), fixed the problem and the program works! I found moving the thread_instance_init() function to the task caused the program to crash. So now everything seems to work!

Edvin · Answer

Hello, 
 We believe the issue is that your function calls are using a lot of timers, which are not supposed to be called until you have kickstarted the FreeRTOS itself using vTaskStartScheduler(). 
 Basically, you can't use any of this: 
 thread_instance_init();
 mqttsn_init();
 
 /* Connect to gateway */ 
 uint32_t err_code = mqttsn_client_search_gateway(&m_client, SEARCH_GATEWAY_TIMEOUT);
 if (err_code != NRF_SUCCESS)
 {
 NRF_LOG_INFO("SEARCH GATEWAY message could not be sent. Error: 0x%x
", err_code);
 }else{
 NRF_LOG_INFO("Search gateway message sendt");
 } 
 before you call vTaskStartScheduler(). Please note that the vTaskStartScheduler does not return, so you need to add these parts e.g. within your openthread task. 
 
 Without being able to pin point exactly what caused the Hardfault it was definitely a timing related issue. The reason it worked in SES was probably due to optimization. When I compiled the DEBUG variant of the project, it hardfaulted, just like your armgcc project. 
 I don't know exactly what it should look like, but look at the unmodified freertos_coap_server example, and do only one change at the time. If it stops working, then look into why it doesn't work. 
 
 Are you sure you really need FreeRTOS anyway? 
 
 BR, 
 Edvin

Openthread with FreeRTOS

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