[En-Nut-Discussion] EIR & RAM-Test

Ulrich Prinz ulrich.prinz at googlemail.com
Wed Oct 17 22:08:43 CEST 2012


You want to check the external RAM?

Some presumptions:
1) You have a Chip with some internal RAM, enough to start a minimal 
Nut/OS (abt. 2..10k should be fine)
2) You have the program in an direct accessible FLASH.
3) Your program consists of threads that use their own stacks, 
initialized on startup of each thread.
4) Your program must be compiled without the external flash mentioned in 
the linker script.

Now you start your main() with enabling your external RAM, checking the 
RAM and then add it to your heap via NutHeapAdd().

As the EIR has an AT91SAM7X256 it hast internal direct accessible FLASH 
and 128k of internal SRAM. So this solution will work for you.

A tip for the RAM test: use a random array of chars using all data 
lines. The size of the array should not match any RAM specs like size of 
RAM, size of columns, size of rows. With that you'll find problems very 


Am 17.10.2012 15:37, schrieb Markus Dost:
> Hi,
> I've build a board of my own based on the EIR and want to check, whether
> the external RAM is connected and working correctly. Is the OS doing
> this during the initialization of the system or do I have to add this?
> I've tried to do the test at the beginning of the NutInit()-routine, but
> the variables for it are stored in the external RAM. Can I force the OS
> not to use the external RAM or maybe somebody had the same plan and can
> give me some tips?
> Best regards,
> Markus
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