hitheshn

DDR2 SI with SAM9G25

Discussion created by hitheshn on Aug 27, 2012
Latest reply on Aug 29, 2012 by hitheshn

I was doing SI simulation of DQ with ATmel SAM9G25 MCU and Micron DDR2-800 memory.With the SAM9G25 set to low drive strength and slow silicon, I dont see anything at the receiver(DDR2).

I didn't get much help from the Atmel app engineer. I don't understand why it's not able to drive. Same case with medium drive strength.

 

I tried with various values of series termination resistors (0-27 ohm). But they made no difference in the above cases. But the drive from DDR2 to MCU works fine.

 

TL length was 1", 50 ohm strip line. The speed was 400MHz.

 

MCU ibis (LFBGA217) -

http://www.atmel.com/tools/SAM9G25-EK.aspx

 

Micron DDR2 ibis -

 

http://www.micron.com/parts/dram/ddr2-sdram/mt47h64m16hr-25

 

One more DDR2-800 question -

 

The external clock speed is 200MHZ

Addr/Ctl/DQS signal max speed is same as clock

Data should be simulated at clock*4, correct?

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