Difference between revisions of "How to place a function in RAM"
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| + | #REDIRECT [[SEGGER_Embedded_Studio]] |
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| − | In some instances it is beneficial to run certain code parts in RAM instead of ROM. For this e.g. a function from ROM needs to be copied at some point into RAM for later usage. |
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| − | The following article will explain how this can be accomplished using Embedded Studio. |
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| − | __attribute__ ((section(".fast"))) |
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| − | void _Delay(void) { |
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| − | } |
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| − | void main(void) { |
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| − | do { |
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| − | Delay(); |
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| − | } while (1); |
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| − | } |
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| − | __TOC__ |
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| − | == Example Setup == |
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| − | The setup guide will be based on the following hardware and software components: |
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| − | * J-Link Software Package V6.30b or later |
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| − | * Embedded Studio V3.34 or later |
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| − | * [https://shop.segger.com/Cortex_M_Trace_Reference_Board_p/6.68.18.htm Cortex-M Trace Reference Board], for other target devices the reference project needs to be adjusted respectively |
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| − | * Any J-Link/J-Trace hardware |
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| − | * Reference Project: [[Media:Generic_RAM_to_ROM_Example.zip | Generic_RAM_to_ROM_Example.zip]] |
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| − | == Setup Guide== |
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| − | The general procedure is as follows: |
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| − | # Generate new project in Embedded Studio using the project wizard or use your already set up project. |
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| − | # Edit the section placement file by right clicking your project in the project explorer and selecting "Edit Section Placement". |
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| − | # Make sure that your section placement file has RAM and ROM memory segments. If not recreate the project or add them manually. |
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| − | # For reference section .fast can be used. |
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| − | # Create a new ROM (Flash) section where to place your future ROM to RAM code in. |
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| − | # Create a new RAM (SRAM) section that has the name you selected in the newly created ROM section for the value runin=".RAMSectionName". |
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| − | # Now the sections have been created. |
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| − | # Go to your application and create e.g. a function that should run in RAM. Place it in your ROM section with the attribute section caller e.g.: void __attribute__((section(".ROMSectionName"))) RunInRAM(int var1, int var2) {} |
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| − | # Before calling the function the first time in your application you first need to move it manually into RAM with the function memcpy: memcpy((void*)&__RAMSectionName_start__, (const void*)&__ROMSectionName_load_start__, (size_t)&__ROMSectionName_size__); |
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| − | # If you now call RunInRAM somewhere in your application the function will run in RAM instead of ROM. |
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| − | For reference the project from section "Example Setup" can be used. |
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Revision as of 17:57, 23 October 2018
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