Ext. MRAM vs Ext. SDRAM targets

[francois_boucha]

Hello,

I want to execute a program from the ext. SDRAM on the m5282evb.  THe program itself comes from the m52259evb which have an external MRAM target.  This program compiles and runs in the SRAM and in FLASH, but wjen it comes to ent SDRAM, it fails to execute.  

How can I execute a program intended to target ext MRAM when my RAM is different?  Is it the linker file that should be checked?

Thx

[JWW]

FB,

Yes... There are differences.  In theory the code should run just fine... once you have the SDRAM configured correctly the SDRAM controller in the 5282 will make the SDRAM look like 'RAM'.  You always need to make sure your linker correctly points the new memory mapped region.

MRAM, SRAM, etc...  Are non-mux'd simple linear memories.  SDRAMs require init code for the SDRAM itself and the controller inside the ColdFire or other microcontroller.  Look at an example codewarrior stationary for the 5282 board that you are using.  In that stationary should be some example code for the SDRAM.

Other places to look for init code:

Try ColdFire Init.

And the MCF5282 example code

Link is HERE

Hope this helps.

-JWW