Quality RTOS & Embedded Software

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


Loading

xSemaphoreGiveFromISR return

Posted by incrediball on March 31, 2010
According to the documentation xSemaphoreGiveFromISR returns pdTRUE if the semaphore was successfully given, otherwise errQUEUE_FULL. What is the meaning of errQUEUE_FULL? Does it mean that the semaphore was already given?

It would be useful for debugging reasons to know if an interrupt is giving a semaphore without a task taking the semaphore. How can this be accomplished?

RE: xSemaphoreGiveFromISR return

Posted by Richard on April 1, 2010
Yes - semaphores are built on top of queues, so when you get the errQUEUE_FULL return value it means the semaphore cannot be given because it is already there. For example, if it is a binary semaphore, you can take the semaphore successfully, then give it successfully once. Once it is given the semaphore is effectively 'full'. If you attempt to give it again without first taking it again you will get this error code returned.

Regards.


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


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

Latest News

FreeRTOS v10.2.1 is available for immediate download. MIT licensed, includes 64-bit RISC-V, NXP Cortex-M33 demo & Nuvoton Cortex-M23 demo.

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

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

Cadence Tensilica Cortes

Espressif ESP32

IAR Partner

Microchip Premier RTOS Partner

RTOS partner of NXP for all NXP ARM microcontrollers

Mediatek

Renesas

RISC-V

SiFIve RISC-V

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