[SI-LIST] Re: DDR-II
- From: "Douglas Burns" <dburns@xxxxxxxxxx>
- To: <npk_0@xxxxxxxxxxx>, <kalevi@xxxxxxxxxx>
- Date: Wed, 30 Mar 2005 08:30:38 -0500
Prakash,
Designing DDRII interfaces is a complex task. Not only do you have issues
with ODT settings, but memory setup and hold times need to be derated by
signal slew rates. SiSoft presented a paper with Micron on DDRII
implementation at Designcon and we also did a tech-forum at PCBWest. The
paper can be found www.sisoft.com/papers.asp . As pointed out earlier, the
issue is not the total number of simulations (though this can be large), but
ensuring that you have set up all of the proper combinations to get the
needed coverage. There is no shortcut for this. Take a look at the paper and
let me know if you have any questions.
Doug
-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx
[mailto:si-list-bounce@xxxxxxxxxxxxx]On Behalf Of Prakash N
Sent: Wednesday, March 30, 2005 12:39 AM
To: kalevi@xxxxxxxxxx
Cc: si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] Re: DDR-II
Hi
When doing our interface design the problem is like this.
We are having seperate 16 bit data for read and write at the controller side
and 8 bit bidirectional data at the memory side. Our interface has some mux,
OCD , ODT etc. Actually we are not doing full controller design rather I/O
part of controller. So while simulating we are not giving address,RAS,CAS
etc,. Only we are having data bits, OE and control bits for OCD,ODT. Now if
we want to simulate the interface there are so many combinations we have to
try, as effectively 32 bit data (seperate 16 bit data for read and write) is
connected to 8-bit data. This simulation takes more time and laborius. Could
anyone suggest how to test effectively so that the time and complexity is
reduced.
My second question is
should we have to put ODT (On-Die termination) on both transmitter and
reciever (both on controller) or it is enough to have ODT in reciever side,
as there is a OCD(off-chip driver) in transmitter side which can take care
of termination.
Regards
Prakash
Kai Keskinen <kalevi@xxxxxxxxxx> wrote:
Simulating 8 bits plus associated clock, address, and strobe should take
about 1 hour to set up and 10 minutes to simulate with an IBIS simulator
like Allegro PCB SI or Mentor's Hyperlynx. What tool are you using? Even
with HSPICE, the set up will take a bit longer but you should be able to
simulate in no more than 1 hour (and probably a lot less) unless you have
very low level encrypted spice models.
-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx
[mailto:si-list-bounce@xxxxxxxxxxxxx]On Behalf Of Prakash N
Sent: Tuesday, March 29, 2005 10:32 AM
To: si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] DDR-II
Hi
I'm doing mini project in DDR-II interface between controller and DDR-II.
Anybody knows how to simulate, as trying to simulate 8 bits will take a
long time. So we have to simplify the simulation with good accuracy. If
anyone knows about simultaing , please help me.
Regards
Prakash
M.E.(Microelectronics Systems)
Centre for Electronics Design & Technology (CEDT)
Indian Institute of Science, Bangalore-560012
Karnataka-India
09448787632
Yahoo! India Matrimony: Find your life partneronline.
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