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Use EMIF

Pablo Cottens
Genius 3020 points
Other Parts Discussed in Thread: HALCOGEN

Hello.

I'd like to use the EMIF connected to a SDRAM (2M) instead of the internal RAM of the microcontroller (256k). How could I achieve that? Is it possible to determine all of this on boot up, or do I have to write a piece of code inside my application to start the EMIF? Do I have to write a bootloader so that it will start that way?

  • 0
    TI__Mastermind 22715 points

    Pablo,

    You need to do the following in order to use external SDRAM in your application.

    (1) Hook up SDRAM to microcontroller's EMIF port following the TRM's EMIF section.

    (2) Set up pinmux to configure the muxed pins for EMIF function.

    (3) Set up EMIF module to work with your SDRAM.

    (2) and (3) have to be down in software. You can create the S/W functions using the halcogen tool or write your own code according to spec.

    In order to achieve the best performance, you will need to use the internal RAM whenever possible. the access speed to SDRAM is much slower.

    Thanks and regards,

    Zhaohong

  • 0 in reply to Zhaohong Zhang
    Genius 3020 points

    I know that the access speed will drop, but I really need to use more RAM than the one on board. 

    And if I wanted to add an external flash for my program? I think this processor doesn't allow to boot from an external flash, so I'd have to connect the flash to the controller, write a bootloader that will move the program to the external flash and then write a startup code that will change the start address of my code?

  • 0 in reply to Pablo Cottens
    TI__Mastermind 22715 points

    Pablo,

    The start address is fixed at 0x0. It is not changeable. There is already 3 MB internal Flash. The following forum threads may provide you with useful information for this topic.

    http://e2e.ti.com/support/microcontrollers/hercules/f/766/p/223034/786205.aspx
    http://e2e.ti.com/support/microcontrollers/hercules/f/312/p/221934/782311.aspx
    http://e2e.ti.com/support/microcontrollers/hercules/f/312/p/199946/730926.aspx
    http://e2e.ti.com/support/microcontrollers/hercules/f/766/t/188446.aspx
    http://e2e.ti.com/support/microcontrollers/hercules/f/312/p/218806/771541.aspx

    Thanks and regards,

    Zhaohong

  • 0 in reply to Zhaohong Zhang
    Genius 3020 points

    Thank you very much Zhaohong. 

    I must say that you and every single TI emplyee I've talked to are incredibly helpful and fast. Simply the best attention to costumers.