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

Porting FreeRTOS to Coldfire MCF5329

Posted by queued on October 29, 2009
Hi!

I'm currently trying to port FreeRTOS to the Coldfire MCF5329, but I'm kind of stuck with the freertos "software" interrupt (for task switching) (the "YIELD interrupt". (On the Coldfire V2 Implementation its Interrupt Source 16 on intc0). Why this is done through interrupt and not through a trap?

Question is: on my implementation on the Coldfire V3 i don't have an unused interrupt 16 and the only unused interrupt in that area is not working (seems to be reserved (interrupt 29 on intc0)).

Thx in advance!!

RE: Porting FreeRTOS to Coldfire MCF5329

Posted by Richard Damon on October 29, 2009
I believe the key thing is that there are several spots which can cause a task reschedule, and they all need to leave the stack in compatible states, these being the YIELD routine and an interrupt requesting a reschedule (either the timer interrupt, or another interrupt that has done something to unblock a task).

RE: Porting FreeRTOS to Coldfire MCF5329

Posted by Richard on October 29, 2009
The interrupt is used as an easy method of supporting interrupt nesting. The interrupt can in effect be 'pended' and then execute when all the other higher priority interrupts have completed. This means any number of interrupts can nest and any number of the nested interrupts can ask for a context switch, but only one will occur. As richard_damon says, it also allows the same method to be used from interrupts as from tasks. Traps are synchronous, so cannot be used in that way.

Any interrupt that can be requested from software, and can have its priority set (in accordance with configKERNEL_INTERRUPT_PRIORITY) can be used.

Regards.


[ 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