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


portTICK_RATE_MS Resolution

Posted by rog57 on December 28, 2012
In the "FreeRTOSConfig.h" file, this is declared:
#define configTICK_RATE_HZ( ( portTickType ) 1000 )

In my program, I have this declared:
#define mainLED_TOGGLE_RATE( ( portTickType ) 5000 / portTICK_RATE_MS )

When I use this:
vTaskDelayUntil( &xLastFlashTime, mainLED_TOGGLE_RATE );

I would expect it to flash every 5 seconds; however, it's flashing at about 7 or 8 seconds. After reading the application manual, I think I understand this topic, but clearly I do not. Can anyone point out the error of my ways?


RE: portTICK_RATE_MS Resolution

Posted by Richard on December 28, 2012
I suspect there will be a mismatch between the configCPU_CLOCK_HZ setting and the actual clock frequency being used.


RE: portTICK_RATE_MS Resolution

Posted by rog57 on December 28, 2012

That was exactly the problem; I displayed all the clock and peripheral registers and updated the value of configCPU_CLOCK_HZ to reflect that value. It's now working fine.

Thanks for the "timely" help!


RE: portTICK_RATE_MS Resolution

Posted by rog57 on December 28, 2012
I also want to say the support I've received on this forum is far better than anything I've paid for from any vendor. Great tool, and the assistance is very appreciated!

[ 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