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


Undefined Priority

Posted by Alexander Zurkan on July 26, 2008
Hi there,

I examined FreeRTOS in depth a little bit the last few days and came across some questions I'd like to discuss with you. I will start a new thread for each question, because they belong to different categories. I also need some webspace for uploading images to explain my other questions, it will take while before I will post them. So lets beginn with the first simple one:

In the FreeRTOS configuration I specified 8 priorities as: #define configMAX_PRIORITIES( ( unsigned portBASE_TYPE ) 8 ).
Then I created a task with a priority of 41. Well, compiling the sources and running it (on ATmega128) shows that everything is working well. Even the task with 41 priority. Examination with a logic analyzer showed, that this task executes as a task with mid Priority such as 3 or 4.

Can anyone explain that behaviour?

Best Regards,

RE: Undefined Priority

Posted by woops_ on July 26, 2008
If you study the source code then you see the code

if( uxPriority >= configMAX_PRIORITIES )
uxPriority = configMAX_PRIORITIES - 1;
so it is limited.

RE: Undefined Priority

Posted by Alexander Zurkan on July 26, 2008
Thanks for the answer. I think I missed that line in the sources.

Best Regards,

[ 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