[Atmega32] second tick hangs on a task with the same priority as others

rafaeladel wrote on Tuesday, January 19, 2016:

I’m a beginner at FreeRTOS, I’ve wrote a simple application that turn on and off between two leds (each task turns a led on and turn off the other).

The problem is i’ve wrote the two tasks but the schedular puts a task in running and switch to the other and stops at this task without switching again.

Maybe i’ve missunderstood how it works. So please help would be appreciated. This is the code i’ve written

#define F_CPU 8000000UL
#include <avr/io.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "freertos/FreeRTOSConfig.h"

void task_one(void *pvParameters);
void task_two(void *pvParameters);

int main(void)
{
    DDRC = 0xff;
	xTaskCreate(task_one, NULL, 50, NULL, 1, NULL);
	xTaskCreate(task_two, NULL, 50, NULL, 1, NULL);
	vTaskStartScheduler();
	return 0;
}

void task_one(void *pvParameters)
{
	while(1) 
	{
		PORTC = 0x0f;
	}
}

void task_two(void *pvParameters)
{
	while(1)
	{
		PORTC = 0xf0;
		
	}
}

edwards3 wrote on Tuesday, January 19, 2016:

Do you know the task is still running ok and not just crashed? What code is executing when you pause the debugger? Does the xTickCount variable in tasks.c increment still?

rafaeladel wrote on Tuesday, January 19, 2016:

Can you tell me how to check this, please ?
I’m trying to access xTickCount via xTaskGetCount(), But don’t know how to check it. Tried printing it on LCD but nothing’s showing up. (LCD is working and code its tested).

edwards3 wrote on Tuesday, January 19, 2016:

How do you know the code is running still?

rafaeladel wrote on Tuesday, January 19, 2016:

I’ve tried converting xTaskGetCount() to string and print it on LCD. Here’s what I got:

  1. xTickCount starts at 0 -> Task_two fires. xTickCount becomes 1 -> Task_one fires. xTickCount stops counting afterwards !
  2. When I put xTaskDelay(1) inside the two tasks. xTickCount increments normally beyond 1 but still it hangs on one task without switching back and fourth.