Quality RTOS & Embedded Software

 Real time embedded FreeRTOS RSS feed 
Quick Start Supported MCUs PDF Books Trace Tools Ecosystem


FreeRTOS heap size issue?

Posted by guggech on January 3, 2018

Hi, I am using FreeRTOS with an Atmel xmega256D3 and using Atmel studio. I am running into a strange issue and hoping that somebody might have some idea on what is going on. I currently have my heap size set 7700 and things seems to work. When I increase the heap size to 7800 or 7900 without excedding the memory boundary, the program does not work, it either keeps resetting, freeze after the power up cycle. I am running 10 tasks which have all been check for stack space. Thanks. Charles

FreeRTOS heap size issue?

Posted by rtel on January 3, 2018

Check the linker script is describing the memory layout of your chip correctly. Perhaps you are trying to use memory that is not physically present.

FreeRTOS heap size issue?

Posted by guggech on January 4, 2018

Is the heap allocated from the high memory to low or the other way?

FreeRTOS heap size issue?

Posted by rtel on January 5, 2018

Can't say for sure if you are using heap_3.c as that maps to the malloc() implementation provided by your compiler, but in all other cases it is low to high.

FreeRTOS heap size issue?

Posted by richard_damon on January 5, 2018

Depends on which heap you are using. heap3.c uses the systems malloc function, which depends on the implementation. The other version use a static array, whose size is set in FreeRTOSConfig.h

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

Copyright (C) Amazon Web Services, Inc. or its affiliates. All rights reserved.

Latest News

Meet Richard Barry and learn what's new in the FreeRTOS project at Embedded World 2019

NXP tweet showing LPC5500 (ARMv8-M Cortex-M33) running FreeRTOS.

Version 10.1.1 of the FreeRTOS kernel is available for immediate download. MIT licensed.

View a recording of the "OTA Update Security and Reliability" webinar, presented by TI and AWS.


FreeRTOS and other embedded software careers at AWS.

FreeRTOS Partners

ARM Connected RTOS partner for all ARM microcontroller cores

Espressif ESP32

IAR Partner

Microchip Premier RTOS Partner

RTOS partner of NXP for all NXP ARM microcontrollers



STMicro RTOS partner supporting ARM7, ARM Cortex-M3, ARM Cortex-M4 and ARM Cortex-M0

Texas Instruments MCU Developer Network RTOS partner for ARM and MSP430 microcontrollers

OpenRTOS and SafeRTOS

Xilinx Microblaze and Zynq partner