> Hi all,
>
> At present, I am using Xilinx SPARTAN XC3S1500 FPGA with Micro MT46V16M16 to do some projects. As my programme is very large, there is not enough space to put them in the bram, so I have to put them in the ddr sdram. However, I found that when the programme is in the ddr sdram, the speed is 20 times lower than in the bram. I couldn't endure it.
>
> Who knows how to speed up the programming in the ddr sdram?
In addition to Antti's suggestion of enabling caches (absolutely
essential), try using Xilinx's new mch_opb_ddr controller, and the
CacheLink interfaces. These bypass the OPB bus for CPU memory accesses,
and also allow wider cachelines than OPB transactions. We see an
instant 2X speedup in real terms on uClinux systems with the MCH caches.
All the info is in the MicroBlaze reference guide. CacheLink is also
supported in Base System Builder, I beleive.
There were some issues with the mch_opb_ddr controller in EDK7.1, no
doubt fixed in 8.1 but hopefully Xilinx will also release a tactical
patch to allow support for 7.1 for the late-adopters - hint hint!
John
Reply by Antti Lukats●January 9, 20062006-01-09
"Athena" <lnzhao@emails.bjut.edu.cn> schrieb im Newsbeitrag
news:ee938f6.-1@webx.sUN8CHnE...
> Hi all,
>
> At present, I am using Xilinx SPARTAN XC3S1500 FPGA with Micro MT46V16M16
> to do some projects. As my programme is very large, there is not enough
> space to put them in the bram, so I have to put them in the ddr sdram.
> However, I found that when the programme is in the ddr sdram, the speed is
> 20 times lower than in the bram. I couldn't endure it.
>
> Who knows how to speed up the programming in the ddr sdram?
>
> Please help me. Thank you very much!
>
> Athena
enable microblaze caches and try again, if you are not using EDK then you
need to implement caches yourself
a poorly designed or badly coupled SDRAM controller can bring very large
slowdown into the system,
--
Antti Lukats
http://www.xilant.com
Reply by Athena●January 9, 20062006-01-09
Micron MT46V16M16 is the ddr sdram that I am using.
Athena
Reply by Athena●January 9, 20062006-01-09
Hi all,
At present, I am using Xilinx SPARTAN XC3S1500 FPGA with Micro MT46V16M16 to do some projects. As my programme is very large, there is not enough space to put them in the bram, so I have to put them in the ddr sdram. However, I found that when the programme is in the ddr sdram, the speed is 20 times lower than in the bram. I couldn't endure it.
Who knows how to speed up the programming in the ddr sdram?
Please help me. Thank you very much!
Athena