Quality RTOS & Embedded Software

 Real time embedded FreeRTOS RSS feed 
Real time embedded FreeRTOS mailing list 
Quick Start Supported MCUs PDF Books Trace Tools Ecosystem TCP & FAT Training


What to do to get round the lack of events?

Posted by Paul Coleman on February 28, 2012
The other day I had a situation where events would have made my life easier... I wanted to wait for three separate threads to reach a particular state before I continued. I didn't know what order the threads would occur in and it could be different each time. Being new to FreeRTOS I started looking in the manual for the section on events only to find that it doesn't support them. So I got round it by using a counting semaphore which the main thread takes three times, then in each of the other three threads I give the semaphore once. Only when the semaphore has been given three times will the main thread continue. This solved my problem but I was wondering if there was a better way I could have achieved this?

Thanks, Paul.

RE: What to do to get round the lack of events?

Posted by Richard Damon on February 28, 2012
There normally is nothing wrong in waiting first for thread1, then thread2, then thread3. If thread3 finishes first, it just says that the wait for it will return immediately.

RE: What to do to get round the lack of events?

Posted by Paul Coleman on February 29, 2012
Yes that's a fair point but it just seemed easier to create one counting semaphore rather than three binary ones. Less resources and less to keep track of :o)


RE: What to do to get round the lack of events?

Posted by Richard Damon on February 29, 2012
As long as you have other synchronizations going so task1 can't give the semaphore twice before task3 gives it once!

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

Copyright (C) 2004-2010 Richard Barry. Copyright (C) 2010-2016 Real Time Engineers Ltd.
Any and all data, files, source code, html content and documentation included in the FreeRTOSTM distribution or available on this site are the exclusive property of Real Time Engineers Ltd.. See the files license.txt (included in the distribution) and this copyright notice for more information. FreeRTOSTM and FreeRTOS.orgTM are trade marks of Real Time Engineers Ltd.

Latest News:

FreeRTOS V9.0.0 is now available for download.

Free TCP/IP and file system demos for the RTOS

Sponsored Links

⇓ Now With No Code Size Limit! ⇓
⇑ Free Download Without Registering ⇑

FreeRTOS Partners

ARM Connected RTOS partner for all ARM microcontroller cores

Renesas Electronics Gold Alliance RTOS Partner.jpg

Microchip Premier RTOS Partner

RTOS partner of NXP for all NXP ARM microcontrollers

Atmel RTOS partner supporting ARM Cortex-M3 and AVR32 microcontrollers

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

Xilinx Microblaze and Zynq partner

Silicon Labs low power RTOS partner

Altera RTOS partner for Nios II and Cortex-A9 SoC

Freescale Alliance RTOS Member supporting ARM and ColdFire microcontrollers

Infineon ARM Cortex-M microcontrollers

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

Cypress RTOS partner supporting ARM Cortex-M3

Fujitsu RTOS partner supporting ARM Cortex-M3 and FM3

Microsemi (previously Actel) RTOS partner supporting ARM Cortex-M3

Atollic Partner

IAR Partner

Keil ARM Partner

Embedded Artists