Forum Discussion

Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
16 years ago

booting out of flash and starting out of DDR2

I have a problem with my DDR2-RAM. I want to boot out of my Flash Device and run the uClinux in my DDR2. The Problem is, that my DDR2 is storing some initalization data in the first regions of t...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
16 years ago

hi!

as far as i know, the ddr2 memory controller uses the first few bytes at startup to calibrate its timings for accesses and destroys data located there.

take a look at the controller user guide from altera http://www.altera.com/literature/ug/ug_ddr_ddr2_sdram_hp.pdf chapter 5, "The Testbench Stages".

additionally it's not the best practice to store initialisation data in volatile memories since you can't rely on the contents after startup or reset situation. collect these data dynamically from the used peripherals or store static data also in the flash.

greetz,

schafrichter