FreeRTOS Support Archive
The FreeRTOS support forum is used to obtain active support directly from Real
Time Engineers Ltd. In return for using our top quality software and services for
free, we request you play fair and do your bit to help others too! Sign up
to receive notifications of new support topics then help where you can.
This is a read only archive of threads posted to the FreeRTOS support forum.
The archive is updated every week, so will not always contain the very latest posts.
Use these archive pages to search previous posts. Use the Live FreeRTOS Forum
link to reply to a post, or start a new support thread.
[FreeRTOS Home] [Live FreeRTOS Forum] [FAQ] [Archive Top] [February 2012 Threads] [STM32F4] Communication betwenn 2 tasksPosted by Ronan on February 10, 2012 Hi!
I 'm learning to use FreeRTOS and I ask myself a question on the communication between 2 task.
In my example, I realise an analog to digital converter on one pin every 100 ms and I send this resultat in a queue.
An other task receives this information by the queue and transmits it at hyperterminal (via UART) every 500 ms.
The problem is that the transmitted data is not the last sampled data.
What is the solution to communicate when 2 tasks don't work at the same frequency ?
thanks,
Ronan.
RE: [STM32F4] Communication betwenn 2 tasksPosted by Richard Damon on February 10, 2012 If task2 just wants the "last" value converted, the best choice is for the data source to just put the value in a global variable and the second task to read from that.
The idea of a queue is to allow a task to wait for data, and to startup as soon as it is available, or if the queue gets full, for the generating task to be delayed, and restarted as soon as there is space to place the data.
Both ends of a queue by definition work at the same average rate, otherwise the queue overflows or underflows.
Copyright (C) Amazon Web Services, Inc. or its affiliates. All rights reserved.
|