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


freeRTOS software timer for ESP32 UART timeout

Posted by blavo1 on March 5, 2017

I'm looking for some example code the shows how to set up a freeRTOS software timer. Basically I'm trying to recieve a fixed packet length on the UART of three consecutive bytes. I created a task that recieves the characters from the UART and builds the 3 byte packet and sends the completed packet via message queue to another task.

Within the task that builds the three byte packet, I'd like to incorporate a timer that will track elapsed time and flag an error if the three bytes aren't recieved within a specified time.

So the process would be this;

Uart character recieved; get initial timer value, start timer ; wait for second byte; check timer elapsed; wait for third byte; check timer elapsed; if three bytes received within the specified time, message off packet to other task with error flag clear else if timer elapsed set error flag and message off to other task with packet array clear clear intial timer value, stop timer

Any help is greatly appreciated.

freeRTOS software timer for ESP32 UART timeout

Posted by rtel on March 5, 2017

How is the task waiting for the bytes? If it is blocking on a queue/event group/semaphore/direct notification, then you can use the timeout in the blocking API call. If the timeout times out then you know it took too long. You can check the RTOS tick count at the start and between bytes to make any adjustments (xTaskGetTickCount()) or even use the vTaskSetTimeout() function.

freeRTOS software timer for ESP32 UART timeout

Posted by blavo1 on March 6, 2017

These are all good ideas and I like the idea of using the timeout in the queue where it's blocking. BTW, I am starting to find more code samples that explain the mechanics of how to do this and I think I have a pretty good idea on how to proceed. Thanks for the 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