FreeRTOS Support Archive
The FreeRTOS support forum is used to obtain active support directly from Real
Time Engineers Ltd. In return for using our top quality software and services for
free, we request you play fair and do your bit to help others too! Sign up
to receive notifications of new support topics then help where you can.
This is a read only archive of threads posted to the FreeRTOS support forum.
The archive is updated every week, so will not always contain the very latest posts.
Use these archive pages to search previous posts. Use the Live FreeRTOS Forum
link to reply to a post, or start a new support thread.
[FreeRTOS Home] [Live FreeRTOS Forum] [FAQ] [Archive Top] [January 2010 Threads] FreeRTOS help with the time to active semaphoPosted by Oliver on January 18, 2010 Hello everybody
I need to improve the time to activate a Semaphore from the ISR. I don't known what solution to apply. The time is about 70 microsecond, maybe because there is a change of task.
Can i implement a different semaphore more fast? Is there another alternative?
Another question. If the interrupt can´t switch the context, can i delete this sentences portENTER_SWITCHING_ISR(); ?
Thank Oliver
Code:
/**************************** INTERRUPT **********************/ _attribute__((__noinline__)) static portBASE_TYPE eic_int_handler_NonNakedBehaviour( void ) { portBASE_TYPE retstatus; portBASE_TYPE xTaskWoken = pdFALSE;
/* Because FreeRTOS is not supposed to run with nested interrupts, put all OS calls in a critical section . */ portENTER_CRITICAL(); retstatus=xSemaphoreGiveFromISR( xSemaphoreReceived, xTaskWoken ); portEXIT_CRITICAL(); /* The return value will be used by portEXIT_SWITCHING_ISR() to know if it should perform a vTaskSwitchContext(). */
if (retstatus) xTaskWoken = pdTRUE;
eic_clear_interrupt_line(&AVR32_EIC, EXT_INT2); return (xTaskWoken); }
__attribute__((__naked__)) void eic_int_handler( void ) { /* This ISR can cause a context switch, so the first statement must be a call to the portENTER_SWITCHING_ISR() macro. This must be BEFORE any variable declarations. */ portENTER_SWITCHING_ISR();
eic_int_handler_NonNakedBehaviour();
/* Exit the ISR. If a task was woken then a context switch will occur. */ portEXIT_SWITCHING_ISR(); }
/************* TASK ******************/ static portTASK_FUNCTION( vTxRxPCUTask, pvParameters ) {
( void ) pvParameters;
//first thing to do Take the Semaphore xSemaphoreTake(xSemaphoreReceived,portMAX_DELAY);
while(1) { //wait for ISR free the semaphore xSemaphoreTake(xSemaphoreReceived,portMAX_DELAY);
//Rest of the code ....... } }
RE: FreeRTOS help with the time to active semaphoPosted by Dave on January 18, 2010 I don't recognize this code, but generally taskENTER_CRITICAL() and taskEXIT_CRITICAL() should not be called from an interrupt. You might consider implementing portSET_INTERRUPT_MASK_FROM_ISR() and portCLEAR_INTERRUPT_MASK_FROM_ISR() which are intended for this type of scenario. If they are not defined then they are just removed using #defines.
RE: FreeRTOS help with the time to active semaphoPosted by Oliver on January 18, 2010 I have an AVR32 in EVK1100. In all example always appear these sentences.
If i don´t change of task in the interrupt, and i don´t call any function of S.O i have deleted this portENTER_CRITICAL(); and portEXIT_CRITICAL();. It´s work! but i don't known if i can delete portENTER_SWITCHING_ISR(); and portEXIT_SWITCHING_ISR(); too. may i delete this sentences?
By the other hand, i want to improve the time beetwen the semaphore from it is given to it is taken Can i create a little code for to comunicate the interrupt with task as soon as posible. this is my problem i have wasted 70 microsecond.
Thanks Oliver
Thanks Oscar
Copyright (C) Amazon Web Services, Inc. or its affiliates. All rights reserved.
|