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From: Morten Leikvoll on 12 Feb 2010 05:19
Using QDRII x18 in 2-burst mode, I assume that the data/adr/cmd bus are all
DDR signals using the same clock domain (except the read and write signal
wich are single data rate)

The docs say there are limitations on where to put the data bus, and then I
can put the adr/cmd on what is left in the bank. This appears to be a bit
weird, as in this mode they are all clocked in at the same DDR(K clk)
domain.

Trying to compile it with swapped pins does give an error like:
"Error: Can't place I/O "d[4]" to I/O location Pin_AG6 because it does not
support x18 mode memory interfaces"
AG6 is not in a x18 DQ bus, but its on the same bank as the other signals in
the domain.

I wonder if anyone got experience with this. Is it just a lazy pinout guide
that dates back from the modes where adr was single data rate? Or is there a
hardware explanation?

Maybe there is a way to override the error message?

(Im clocking at half the max allowed, so there should be some overhead in
timing)


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