Quality RTOS & Embedded Software

 Real time embedded FreeRTOS RSS feed 
Quick Start Supported MCUs PDF Books Trace Tools Ecosystem


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) Amazon Web Services, Inc. or its affiliates. All rights reserved.

Latest News

Meet us at Embedded World. Hall 3A-525.

Hear from Richard Barry at Embedded World. Feb 28, 16:00, Hall 4-428.

Video: Watch James Gosling & Richard Barry at re:Invent, Las Vegas 2017.

FreeRTOS kernel V10.0.1 is available for immediate download. Now MIT licensed.

FreeRTOS Partners

ARM Connected RTOS partner for all ARM microcontroller cores

IAR Partner

Microchip Premier RTOS Partner

RTOS partner of NXP for all NXP ARM microcontrollers

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

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

OpenRTOS and SafeRTOS