Mbed RTOS Multiple tasks are not running Nucleo-F072RB

Mbed OS
1

Hi,

I’m starting to understand and learn about RTOS and I wanted to test a simple code to run two tasks in a Nucleo-F072RB, however, I am only able to run 1 task and I am not able to get to my task #2. I may need something else in my code but I would like to get some support from you guys and that way I could understand it better. (Hopefully).

#include "mbed.h"

 

DigitalOut led1(LED1);

DigitalOut led2(PC_1);

Thread thread1;

Thread thread2(osPriorityBelowNormal);

#define WAIT_T1 100

#define WAIT_T2 500

 

void led1_thread() {

    while (true) {

        led1 = !led1;

        ThisThread::sleep_for(WAIT_T1);

    }

}

 

void led2_thread() {

    while (true) {

        led2 = !led2;

        ThisThread::sleep_for(WAIT_T2);

    }

}

 

int main() {

    thread1.start(led1_thread);

    thread2.start(led2_thread);

}

What I want to do is to run both tasks, I know there is no simultaneously tasks running at the same time, but I am hoping to get one task… then run the other… and so on.

I am also aware that main() function is a main thread but I was hoping to handle tasks in different handlers (functions).

How can I do that?

2

I think that main needs a while loop with a sleep inside.

3

Hello Fabian,

Your code runs OK on a NUCLEO-F103RB (20kB SRAM). Maybe the NUCLEO-F072RB (16kB SRAM) doesn’t have sufficient SRAM to run correctly such program. To learn RTOS I would suggest to get a board with more SRAM (32kB and more). At the moment the STM32F401 (96kB SRAM, 4.55$ on eBay) and STM32F411 (128kB SRAM, 4.88$ on eBay) development boards seem to have a very good price-to-SRAM ratio. The STM32F407VET6 (128kB + 64kB SRAM) development board, with on-board SD card slot, 16Mbit SPI Flash memory and battery holder, could be also a good (low cost) choice. Then you can use the NUCLEO-F072RB as a programmer.

Best regards, Zoltan

4

Ahoj,

If it really the issue about memory resources, how Zoltan wrote, as an alternative you can try the EventQueue under the Mbed OS bare metal profile.

BR, Jan

5

Hello,

Thanks for your reply and considerations. I changed my code to print messages to my serial terminal:

#include "mbed.h"

 

//DigitalOut led1(LED1);
//
//DigitalOut led2(PC_1);

Thread thread1;

Thread thread2(osPriorityBelowNormal);

#define WAIT_T1 100

#define WAIT_T2 500

Serial pc(USBTX, USBRX);

void led1_thread() {

    while (true) {

//        led1 = !led1;
        pc.printf("hello-task-1\r\n");

        ThisThread::sleep_for(WAIT_T1);

    }

}

 

void led2_thread() {

    while (true) {

//        led2 = !led2;
        pc.printf("hello-task-2\r\n");

        ThisThread::sleep_for(WAIT_T2);

    }

}

 

int main() {

    thread1.start(led1_thread);

    thread2.start(led2_thread);

}

I also have other STM32 boards here to test, I used a Nucleo-F411RE and the code run it succesfully!

Then I tested my code in the Nucleo F072RB and I saw this in the terminal:

++ MbedOS Error Info ++
Error Status: 0x8001011F Code: 287 Module: 1
Error Message: Operator new[] out of memory

Location: 0x8004D31
Error Value: 0x1000hell
Current Thread: main  Id: 0x200014D4 Entry: 0x8005E79 StackSize: 0xC00 StackMem: 0x200003C8 SP: 0x20000F18

So yes, it is running out of memory.

I was thinking and I would like to know from your side if is possible to change the stack size and then maybe able to run several tasks in this board ?

Mostly because I previously tested FreeRTOS in STM32Cube framework and there I was able to run multiple tasks/threads (I simply ran 2 threads, did not test more than that).

6

You can supply the stacksize in the constructor of the Thread class, the default is 4 kB.