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


Interrumption problems

Posted by Nobody/Anonymous on April 16, 2007

I'm working some days ago with the FREErtos and PIC18F8621...i have to work with 3 metal sensor, we use the timer0 to create the interruption each 800ms. This process is periodic so each 800ms one of this 3 sensor will turn on and make some operation and after the other and the other. I tried to use the vTaskDelay but the program didn't work well....

So I don't know if i can do use it with the Freertos.. I mean use the timer0 for interruption into the freertos.... can you help me with some ideas?? I really need your help!!...

Thanks so much for your help, have a nice day!!


RE: Interrumption problems

Posted by Nobody/Anonymous on April 16, 2007
How does vTaskDelay() interact with your timer? You could use vTaskDelayUntil() to cause a task to run every 800ms. Alternatively if the function is short you could use a tick hook function in place of a task.


RE: Interrumption problems

Posted by Nobody/Anonymous on April 16, 2007
Thanks so much for your help, it looks really fine!!!

I found example for the vtaskdelayuntil:

void vTaskFunction( void * pvParameters )
portTickType xLastWakeTime;
const portTickType xFrequency = 10;

// Initialise the xLastWakeTime variable with the current time.
xLastWakeTime = xTaskGetTickCount();
for( ;; )
// Wait for the next cycle.
vTaskDelayUntil( &xLastWakeTime, xFrequency );

// Perform action here.

and also it said that we can use the constant portTICK_RATE_MS to calculate real time..... but i only found this constant:

#define portTICK_RATE_HZ ( ( portTickType ) 400 )

so i can use it for calculation 800ms? or can I say that my const portTickType xFrequency = 0.800;....

Thanks so much for your help!!!...i can't understand the relation betwen ticks and constant... thanks again for your help...


[ 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