Quality RTOS & Embedded Software
About   Contact   Support   FAQ

 Real time embedded FreeRTOS RSS feed 
Real time embedded FreeRTOS mailing list 
Quick Start Supported MCUs Books & Kits Trace Tools Ecosystem TCP & FAT Training

Last site update June 02 2015

The AVR Context
[RTOS Implementation Building Blocks]

A context switch requires the entire execution context to be saved. On the AVR microcontroller the context consists of:
  • 32 general purpose processor registers. The gcc development tools assume register R1 is set to zero.
  • Status register. The value of the status register affects instruction execution, and must be be preserved across context switches.
  • Program counter. Upon resumption, a task must continue execution from the instruction that was about to be executed immediately prior to its suspension.
  • The two stack pointer registers.


Next: RTOS Implementation - Saving The Context

[ Back to the top ]    [ About FreeRTOS ]    [ Sitemap ]    [ ]

Copyright (C) 2004-2010 Richard Barry. Copyright (C) 2010-2015 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 - New Book Edition!

Receive a complimentary pre-release pdf of our up-coming book "Mastering the FreeRTOS Real Time Kernel, a Hands-On Tutorial Guide" with every purchased copy of the existing "Using the FreeRTOS Real Time Kernel" book.

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

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