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




Loading

Best practice to share same resources between tasks

Posted by chaabanemalki on March 12, 2015

Hello,

I'm working on a project where I have to write to an SD card from more than one task. For this I use mutex. I use SPI to communicate with the SD card, plus I have to use an EEPROM that share the same SPI bus witht he SD card. First idea that came in my mind is to use one mutex to share the SPI bus between SD card and EEPROM and also between different tasks that write/read from the SD card.

Is there a better efficient way to manage my case ?


Best practice to share same resources between tasks

Posted by davedoors on March 12, 2015

Mutex is a good option for you. It will be obtained by the highest priority thread waiting on it, and has priority inheritance.


Best practice to share same resources between tasks

Posted by richard_damon on March 12, 2015

This sounds like the classic use of a mutex.

The minor nit is that it seems you are making public an implementation detail (the SD card and the EEPROM are on the same bus), but the actual mutex access can be put into the device driver APIs.

There could be some argument for having a second mutex outside the SPI bus mutex for just the SD card (or just the EEPROM) if the application layer needs to do multiple transactions that need to stay "atomic" (like reading a sector to update it). With just a single mutex, the task would need to lock out the EEPROM too during the update cycle.


Best practice to share same resources between tasks

Posted by chaabanemalki on March 13, 2015

Thank you 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