Forum Discussion

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

Nios crashes when reading from the DDR2

Hi, I'm trying to setup the DDR2 as a frame buffer for streaming to a display. Currently, I am able to write and read pixels to and from the off-chip DDR2 and communicate with custom ha...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
16 years ago

I figured out where to get the values for slew rate derating with DDR2. If anyone else who is relatively new at this has the same problem, this might help.

This pdf has some good info on what the values actually mean.

http://www.ansoft.com/si/pdf/memory_made_easy.pdf

And I used the equations given in this user guide:

http://www.altera.com/literature/hb/external-memory/emi_tut_ddr.pdf

The base values, Tis(base) etc., I found from the memory vendor data sheet.

For the time being, I am going to assume the same slew rate values as the Stratix III dev board. (I'm using the DE3 board).

This will hopefully give me the right timing in order to fix the erratic errors occurring when reading from the DDR2.

Andrew