configTICK_RATE_HZ in ATmega16

Kernel
1

nobody wrote on Tuesday, May 15, 2007:

Hello :slight_smile:

My name is Jorge Pinto from Portugal. I have FreeRTOS working and I am happy, because I started about 8 months ago looking for a RTOS with just FreeSoftware, and realy like GCC-AVR and FreeRTOS :slight_smile:

Well, the problem, I have one test code that flash a LED every some time, but, I would like to change the configTICK_RATE_HZ for a lower value, however, If I change it, It does not have result :frowning:

My config:
#define configCPU_CLOCK_HZ            ( ( unsigned portLONG ) 8000000 )

#define configTICK_RATE_HZ            ( ( portTickType ) 20 ) // 20 instead of original 1000!!

The task the flash the LED:
/*-----------------------------------------------------------*/
/*
#
# Task que vai ligar ou desligar o LED.
#
*/

static void vFlashLED( void *pvParameters )

{

/* The parameters are not used. */

( void ) pvParameters;

portTickType xLastWakeTime;
const portTickType xFreq_ligado = 2000; // 2 segundos
const portTickType xFreq_desligado = 1000; // 1 segundo

    /* Cycle for ever. */

    for( ;; )

        {

        // Ligar LED
        PortCLatch = PORTC;
        PORTC = (PortCLatch | (1 << 0));

        // Initialise the xLastWakeTime variable with the current time.
        xLastWakeTime = xTaskGetTickCount();
        vTaskDelayUntil( &xLastWakeTime, xFreq_ligado );

        // Desligar LED
        PortCLatch = PORTC;
        PORTC = (PortCLatch & (0 << 0));

        // Initialise the xLastWakeTime variable with the current time.
        xLastWakeTime = xTaskGetTickCount();
        vTaskDelayUntil( &xLastWakeTime, xFreq_desligado );

        }

}

If I change xFreq_ligado and xFreq_desligado, the flash time alters, but not If I change configTICK_RATE_HZ :frowning:

—

Another question, I have this macro:

#define #define FlashLED (0); (0);

and If a do: PORTC = (PortCLatch & (0 << (FlashLED) )); I get an error?? Why?? - I am doing this instead: PORTC = (PortCLatch & (0 << 0));

Thanks in advance.

Jorge Pinto
http://www.Casainho.net

2

rtel wrote on Wednesday, May 16, 2007:

Take a look at the function prvSetupTimerInterrupt() in port.c for the GCC/AVR port.  It might be that the compare match value written to the timer peripheral is overflowing because you are dividing the clock frequency by such a low number (20 instead of 1000).  If this is the case then you might need to adjust the timer prescale, or do something similar.

Regards.

3

nobody wrote on Thursday, May 17, 2007:

I figured it out :slight_smile: After trying change same values on the prvSetupTimerInterrupt(), I did discover the real problem :slight_smile: LOL

I work on Linux and I was on this directory: “/media/data/05_assembly/ATMEL/FreeRTOS/Demo/AVR_ATMega323_WinAVR” and I also had this one “/media/data/05_assembly/ATMEL/FreeRTOS/Demo/AVR_ATMega323_WinAVR-copy”. I don’t know why, but looks like the system was using the “FreeRTOSConfig.h” from directory “AVR_ATMega323_WinAVR-copy” instead of that where I was working “AVR_ATMega323_WinAVR”!!

Now all works ok after delete "AVR_ATMega323_WinAVR-copy" :wink: :slight_smile:

Thank you and please continue with this great work - FreeRTOS. I am using and have good experiences so I recommend to all my friends :slight_smile:

4

casainho wrote on Wednesday, May 30, 2007:

Oh men, I was wrong :wink: :slight_smile:

I must do “make clean” after change “FreeRTOSConfig.h” file!! If I don’t do “make clean”, changes in “FreeRTOSConfig.h” file don’t have effect.

—
http://www.Casainho.net