Hi, I am working on TI CortexM4 microcontroller running FreeRTOS. I am trying to toggle a pin on microcontroller. I have noticed the GPIO port is toggling at very slow speed of 3.9usec, while the micrcontroller is running at 120MHz. I have tried the same code without FreeRTOS and the toggling becomes very fast i.e. 150nsec. My project has no interrupts running and here is the code i am running under FreeRTOS; Please note, I have removed the hash sign infront of includes files as the posting system of sourceforge some how doesnt like it. include <stdint.h> include <stdbool.h> include “main.h” include “drivers/pinout.h” include “utils/uartstdio.h” // TivaWare includes include “driverlib/sysctl.h” include “driverlib/debug.h” include “driverlib/rom.h” include “driverlib/rommap.h” include “driverlib/gpio.h” include “driverlib/inc/hwmemmap.h” // FreeRTOS includes include “FreeRTOSConfig.h” include “FreeRTOS.h” include “task.h” include “queue.h” define SYSTEM_CLOCK 120000000U // Demo Task declarations void demoLEDTask(void *pvParameters); void demoSerialTask(void *pvParameters); // Main function int main(void) { // Initialize system clock to 120 MHz uint32t outputclockratehz; outputclockratehz = ROMSysCtlClockFreqSet( (SYSCTLXTAL25MHZ | SYSCTLOSCMAIN | SYSCTLUSEPLL | SYSCTLCFGVCO480), SYSTEMCLOCK); ASSERT(outputclockratehz == SYSTEMCLOCK);

// Initialize the GPIO pins for the Launchpad
PinoutSet(false, false);

ROM_GPIOPinTypeGPIOOutput(GPIO_PORTM_BASE, GPIO_PIN_4 | GPIO_PIN_5 );
GPIOPadConfigSet(GPIO_PORTM_BASE, GPIO_PIN_4 | GPIO_PIN_5, GPIO_STRENGTH_2MA, GPIO_PIN_TYPE_STD);
// Create demo tasks
xTaskCreate(demoLEDTask, (const portCHAR *)"LEDs",
            configMINIMAL_STACK_SIZE, NULL, 2, NULL);

xTaskCreate(demoSerialTask, (const portCHAR *)"Serial",
            configMINIMAL_STACK_SIZE, NULL, 1, NULL);

vTaskStartScheduler();
return 0;

} // Flash the LEDs on the launchpad void demoLEDTask(void *pvParameters) {

for (;;)

{
    GPIOPinWrite(GPIO_PORTM_BASE,GPIO_PIN_4 |GPIO_PIN_5 ,0);
    //for(i=0;i<1;i++){}
    //SysCtlDelay(1);
    GPIOPinWrite(GPIO_PORTM_BASE, GPIO_PIN_4 | GPIO_PIN_5, GPIO_PIN_4 | GPIO_PIN_5);

}

} // Write text over the Stellaris debug interface UART port void demoSerialTask(void *pvParameters) {

// Set up the UART which is connected to the virtual COM port
UARTStdioConfig(0, 57600, SYSTEM_CLOCK);


for (;;)
{
    UARTprintf("rnHello, world from FreeRTOS 9.0!");
    vTaskDelay(5000 / portTICK_PERIOD_MS);
}

} /* ASSERT() Error function * * failed ASSERTS() from driverlib/debug.h are executed in this function */ void error(char *pcFilename, uint32_t ui32Line) { // Place a breakpoint here to capture errors until logging routine is finished while (1) { } } And here is the scope snapshot

If you want to include source code in a post, please enclose the code between two lines that contain 3 tilda’s (~~~) only, like this: ~~~ ~~~ void foo() { } ~~~ ~~~ In general: code should not run slower under FreeRTOS, but you have to realise that the CPU is being shared with other tasks. In your example, the kernel ( the idle task ) will be sleeping 99.99% of the time. Now here is the essence of your code: ~~~ // Create demo tasks xTaskCreate(demoLEDTask, (const portCHAR *)”LEDs”, configMINIMAL_STACK_SIZE, NULL, 2, NULL); xTaskCreate(demoSerialTask, (const portCHAR *)”Serial”, configMINIMAL_STACK_SIZE, NULL, 1, NULL); // Flash the LEDs on the launchpad void demoLEDTask(void *pvParameters) { for (;;) { GPIOPinWrite(GPIO_PORTM_BASE,GPIO_PIN_4 |GPIO_PIN_5 ,0); GPIOPinWrite(GPIO_PORTM_BASE, GPIO_PIN_4 | GPIO_PIN_5, GPIO_PIN_4 | GPIO_PIN_5); } } // Write text over the Stellaris debug interface UART port void demoSerialTask(void *pvParameters) { for (;;) { UARTprintf(“rnHello, world from FreeRTOS 9.0!”); vTaskDelay(5000 / portTICK_PERIOD_MS); } } ~~~ I’d like to say something about your demoLEDTask(): it has an eternal loop that will never block ( or sleep ). I wonder if your second task demoSerialTask(), which has a lower priority, ever gets CPU time? If you really want to have a task that never blocks, I recommend you let it run on the Idle priority 0.

Hi Sahil, have you discovered what the problem was?