Quality RTOS & Embedded Software

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


xSemaphoreGiveFromISR() problems

Posted by Ruben Logan on January 7, 2013
I have two ISRs using xSemaphoreGiveFromISR() fuction call and one over a long period of time never gets called and the other has missed its call here and there. I suspect that there is a priority issue with this function that causes it to fail. I am using version 7 of freeRTOS. Has anyone had this issue where the ist just gets blocked?

RE: xSemaphoreGiveFromISR() problems

Posted by Richard on January 8, 2013
Which port are you using?
What type of semaphore is it (binary/counting/etc.)?

“one over a long period of time never gets called”

What doesn't get called? The ISR? What is triggering the ISR (UART, DMA, SPI, external, etc.)? Are you sure the ISR is configured and cleared correctly? [topics which are outside of FreeRTOS support]

“the other has missed its call here and there”

What has missed its call? The interrupt? Do you have critical sections that are too long for the frequency at which the interrupts are arriving?


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

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

Latest News

FreeRTOS v10.2.0 is available for immediate download. MIT licensed, and including RISC-V and ARMv8-M (Cortex-M33) demos.

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.


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





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