µVISION DEBUGGER: Flashing Atmel AT91 Devices to XRAM

Information in this article applies to:

• µVision Version 2 and Later

QUESTION

I'm having problems loading a program into the XRAM of the Atmel EB55 Evaluation Board (Atmel AT91 Series). 

Does the Atmel AT91 series have any special requirements for downloading to XRAM?

ANSWER

Yes. The Atmel AT91 devices require a REMAP command in the user-startup code to access the on-board XRAM memory. Without the REMAP command, only the internal RAM and onboard FLASH can be addressed.

The Keil ARM installation contains the proper startup code in the ARM\xxx\Startup\Atmel folder. You can copy the startup code Startup.s from this location to your project folder.

You also require a Linker Script (.ld) file and a debugger (.ini) file to setup the device for loading to XRAM. The phyCORE XRAM target in the Blinky project Boards\Phytec\AT91M55800A\Blinky is a good example of how to do this. It contains:

• The Startup.s file with the REMAP command.
• The Text Start and Data Start addresses in XRAM for the linker target options.
• The linker script file phyXRAM.ld configured for downloading to XRAM. The Code Start and Data Start addresses in this file match the Text Start, and Data Start addresses in the linker target options.
• The debugger file XRAM.ini that sets the REMAP command and configures the external bus prior to loading the Blinky application program. Notice that the Program Entry Point in this file matches the Code Start address above.

The Blinky program downloads to and runs in XRAM.

Copy the Startup.s, phyXRAM.ld, and XRAM.ini files from the Boards\Phytec\AT91M55800A\Blinky folder to your project folder. Add the phyXRAM.ld as your Linker Script File, and the XRAM.ini as your debug Initialization File. You may have to change the Code Size and Data Size values in the phyXRAM.ld file to suit your code and data requirements.

SEE ALSO

• ULINK: ARM DEBUGGER CRASHES
• ULINK: Atmel Flash Shows Wrong Values

Last Reviewed: Monday, January 11, 2021