you are also confusing the ddr specification which is actually in Mbps not MHz. The relationship is a 400MHz interface will equate to an 800 Mbps ddr3.
On Mon, Oct 24, 2016 at 10:19 PM, Teoh Choon Zone < choon-zone.t...@vie.com.my> wrote: > > On Tue, Oct 25, 2016 at 1:12 PM, Phil Reid <pr...@electromag.com.au> > wrote: > >> On 25/10/2016 12:59, Teoh Choon Zone wrote: >> >>> Based on http://www.digikey.com/en/product-highlight/a/altera/cyclone >>> -v-fpga-family , it says "Hard-memory controllers supporting 400 MHz >>> DDR3 SDRAM with >>> optional error correction code (ECC) support". Let say if I use DDR3 >>> with 1866MHz speed grade. What frequency will it actually run at? What is >>> the relationship >>> between memory controller and DDR3 speed grade? >>> >>> 400Mhz. >> Also be aware that the Cyclone V don't support DDR3 fly-by topologies. >> Which means plug in ddr3 DIMMS are not usuable. >> >> http://www.alteraforum.com/forum/archive/index.php/t-35838.html > > > > So there is no point to use higher speed grade when the DDR3 frequency is > capped at 400MHz? I tried to use timing parameter for 1600MHz on 1866MHz > DDR3, Linux boots just fine and u-boot mtest does not give any error after > run for 24 hours. So are the preloader can be used interchangeably? If yes, > we could minimize the firmware variation during mass production. FYI, we > change our DDR3 speed grade to 1866 because 1600 has been phased out by > Micron. > > _______________________________________________ > Rfi mailing list > Rfi@lists.rocketboards.org > http://lists.rocketboards.org/cgi-bin/mailman/listinfo/rfi > >
_______________________________________________ Rfi mailing list Rfi@lists.rocketboards.org http://lists.rocketboards.org/cgi-bin/mailman/listinfo/rfi
