Place Functions in RAM with SEGGER Linker

This article will show how to place a function into RAM with SEGGER Linker and Embedded Studio.

How to

• Create a symbol or function you want to place in RAM
• Open the SEGGER Linker script file and place the specific symol in RAM. This can be done e.g. as follows (or in one of the other ways documented ):

place in RAM1 {symbol MySymbol};

• To make sure this stays valid after a reset/reboot of the device the library functions must be initialized during startup by copying them from Flash to RAM. That way the application also works stand alone without a debugger.
• This can be done by adding the following line to the remaining "initialize by copy entries".

initialize by copy { section .text.MySymbol, section .text.MySymbol.* };

Example project

The following example project will show an example implementation of such RAM function. A simple function Count() is created which is placed in RAM and executed.

Prerequisites

To be able to build and debug the project the following prerequisites must be met:

• SEGGER Embedded Studio V4.52c or later
• Any J-Link
• Cortex-M Trace Reference Board

Project files

RAMFunc_Example.zip