The FreeRTOS kernel is now an MIT licensed AWS open source project, and these pages are being updated accordingly.

Quality RTOS & Embedded Software About   Contact   Support   FAQ   Download Menu      Quick Start Supported MCUs PDF Books Trace Tools Ecosystem Quick Start Guide Support Forum ⇓ Download Source ⇓ FreeRTOS+ Ecosystem  FreeRTOS+TCP:  Thread safe TCP/IP stack  SafeRTOS:  TUV certified RTOS  OpenRTOS:  Commercial Licensed RTOS  Fail Safe File System:  Ensures data integrity  FreeRTOS BSPs:  3rd party driver packages  Trace & Visualisation:  Tracealyzer for FreeRTOS  CLI:  Command line interface  WolfSSL SSL / TLS:  Networking security protocols  RTOS Training:  Delivered online or on-site  IO:  read(), write(), ioctl() interface FreeRTOS+ Lab Projects  FreeRTOS+POSIX:  POSIX threading API  FreeRTOS+FAT:  Thread aware file system Hint: Use the tree menu to navigate groups of related pages   xSemaphoreTakeFromISR [Semaphores] semphr. h xSemaphoreTakeFromISR ( SemaphoreHandle_t xSemaphore, signed BaseType_t *pxHigherPriorityTaskWoken ) A version of xSemaphoreTake() that can be called from an ISR. Unlike xSemaphoreTake(), xSemaphoreTakeFromISR() does not permit a block time to be specified. Parameters: xSemaphore  The semaphore being 'taken'. A semaphore is referenced by a variable of type SemaphoreHandle_t and must be explicitly created before being used. pxHigherPriorityTaskWoken  It is possible (although unlikely, and dependent on the semaphore type) that a semaphore will have one or more tasks blocked on it waiting to give the semaphore. Calling xSemaphoreTakeFromISR() will make a task that was blocked waiting to give the semaphore leave the Blocked state. If calling the API function causes a task to leave the Blocked state, and the unblocked task has a priority equal to or higher than the currently executing task (the task that was interrupted), then, internally, the API function will set *pxHigherPriorityTaskWoken to pdTRUE. If xSemaphoreTakeFromISR() sets *pxHigherPriorityTaskWoken to pdTRUE, then a context switch should be performed before the interrupt is exited. This will ensure that the interrupt returns directly to the highest priority Ready state task. The mechanism is identical to that used in the xQueueReceiveFromISR() function, and readers are referred to the xQueueReceiveFromISR() documentation for further explanation. From FreeRTOS V7.3.0 pxHigherPriorityTaskWoken is an optional parameter and can be set to NULL. Returns: pdTRUE if the semaphore was successfully taken. pdFALSE if the semaphore was not successfully taken because it was not available. [ 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