Using Multiple Memory Regions with the FreeRTOS Heap

ARM Cortex-M microcontrollers can have multiple memory controllers. This is a good thing as it allows the hardware to do multiple parallel memory read/writes. However this makes the memory map more complicated for the software: it divides the memory into different regions and memory segments.  This article is about how to enable FreeRTOS to use multiple memory blocks for a virtual combined memory heap:

FreeRTOS with Segmented Heap Memory

FreeRTOS with Segmented Heap Memory

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Using FreeRTOS with newlib and newlib-nano

For reliable applications, I avoid using functions of the standard libraries. They are banned for most safety related applications anyway. I do not use or avoid malloc(), printf() and all the other variants, for many reasons including the ones listed in “Why I don’t like printf()“. Instead, I’m using smaller variants (see “XFormat“). Or I’m using only the thread-safe FreeRTOS heap memory allocation which exist for many good reasons.

Things get problematic if malloc() still is pulled in, either because it is used by a middleware (e.g. TCP/IP stack) or if using C++. Dave Nadler posted a detailed article (http://www.nadler.com/embedded/newlibAndFreeRTOS.html) about how to use newlib and newlib-nano with FreeRTOS.

FreeRTOS Newlib Memory Allocation Scheme

FreeRTOS Newlib Memory Allocation Scheme

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