Quality RTOS & Embedded Software

 Real time embedded FreeRTOS RSS feed 
Quick Start Supported MCUs PDF Books Trace Tools Ecosystem


Loading

xQueueSelectFromSet set order

Posted by https://www.google.com/accounts on February 27, 2013
In which order are returned queues or semaphores if e.g. both binary semaphores were given?

I mean a use case on ARM CM3. During ISR0 a binary semaphore A is given . Meanwhile a different interrupt with the same priority occurs, it is pended waiting for the end of the ISR0. The ISR1 gives a semaphore B.

Both semaphores (A and B) belongs to a queue set C and were added in this order xQueueAddToSet(A), xQueueAddToSet(B).

If I call xQueueSelectFromSet(C) before ISR0, will be the semaphore A returned? And if I call xQueueSelectFromSet(C) again, will be the semaphore B returned immediately?

Thank you for explanation.

Martin Velek


RE: xQueueSelectFromSet set order

Posted by Richard on February 27, 2013
The order in which queues are added to a queue set is not important. The queue set reports events in the order in which the events are received. Therefore if semaphore A and semaphore B are in the same set, and semaphore A is given before semaphore B, then the queue set returns the handle of semaphore A first whatever. Likewise if semaphore B is given before semaphore A then the queue set will return the handle of semaphore B whatever.

Hope this helps.

Regards.


[ Back to the top ]    [ About FreeRTOS ]    [ Privacy ]    [ Sitemap ]    [ ]


Copyright (C) Amazon Web Services, Inc. or its affiliates. All rights reserved.

Latest News

NXP tweet showing LPC5500 (ARMv8-M Cortex-M33) running FreeRTOS.

Meet Richard Barry and learn about running FreeRTOS on RISC-V at FOSDEM 2019

Version 10.1.1 of the FreeRTOS kernel is available for immediate download. MIT licensed.

View a recording of the "OTA Update Security and Reliability" webinar, presented by TI and AWS.


Careers

FreeRTOS and other embedded software careers at AWS.



FreeRTOS Partners

ARM Connected RTOS partner for all ARM microcontroller cores

Espressif ESP32

IAR Partner

Microchip Premier RTOS Partner

RTOS partner of NXP for all NXP ARM microcontrollers

Renesas

STMicro RTOS partner supporting ARM7, ARM Cortex-M3, ARM Cortex-M4 and ARM Cortex-M0

Texas Instruments MCU Developer Network RTOS partner for ARM and MSP430 microcontrollers

OpenRTOS and SafeRTOS

Xilinx Microblaze and Zynq partner