SDRAM

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    Jon Elliott

    Regarding the "Memory erase operation failed: no driver installed for memory range" error, see http://rowley.zendesk.com/entries/45571-no-driver-installed-for-memory-range-error-message - For more information on LIBMEM and loaders see http://www.rowleydownload.co.uk/documentation.latest/arm/libmem.htm and http://www.rowleydownload.co.uk/documentation.latest/arm/libmem_loader.htm

    If you want to write an application that boots from FLASH and uses external SDRAM then you probably don't want to download to SDRAM at all. For .bss this is simply a case of setting the "Load" attribute in the placement file to "No". For .data (and .rodata if you want that in RAM as well) you will need to set up a "load" and a "run" section. The default FLASH placement files we ship all setup "load" and "run" sections for .data.

    You would normally configure SDRAM in your startup code so that it is configured before crt0.s initialises .bss and copies .data.

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    stefano marini

    OK I saw that into the crt0.s file there is a place in which is possible to initialize the secondary memory section (this is into the piece of code between

    #ifdef INITIALIZE_SECONDARY_SECTIONS) and #endif

     

    Now I suppose that the SDRAM has to be initialized before this piece of code.

    Is There a specific place into the crt0.s or into the _Startuo.s files to initialize the SDRAM?

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    Qing

    My experience is to add the configuration code in the _Startup.s code just before b _start. In the application note about SDRAM, there are sample codes in C for that. I rewrite it in Assembly language, and it is for the AT91SAM7SE-EK demo board from Atmel. After that, check with the Memory Map file and Section Placement file to make sure when building the project, some code will be put in the external SDRAM. Also, it is able to put some test code for SDRAM, like to write some data to a sequence of address and read them later. It should be OK if the SDRAM parameters are properly set up.

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    Jon Elliott

    Stephen,

    Thanks, links now updated.

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