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Visitor gir2004
Visitor
14,438 Views
Registered: ‎12-18-2007

help in using microblaze with external DDR memory on Spartan 3E

Hi,
 
I'm a beginner in using the EDK tool to design a system that uses the microblaze and the on board DDR memory. I started with the BSB and created a test project that is supposed to test the DDR SDRAM. After downloading the program, it freezes when attempting to test the external memory. Does anyone know how to deal with this? Also I would appreciate help on how to use the external DDR memory for program executable code and data?
 
Thanks,
 
Girma
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9 Replies
Explorer
Explorer
14,431 Views
Registered: ‎09-16-2007

Re: help in using microblaze with external DDR memory on Spartan 3E

Make sure you run out of block ram and not ddr memory.   How much block ram do you have?
 
Cheers,
Bill Tomb
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Visitor gir2004
Visitor
14,419 Views
Registered: ‎12-18-2007

Re: help in using microblaze with external DDR memory on Spartan 3E

According to the spec the FPGA has 360 Kbits block ram. The board I'm using is Xilinx's Spartan 3E which comes with 64MByte of DDR SDRAM.
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Explorer
Explorer
14,416 Views
Registered: ‎08-30-2007

Re: help in using microblaze with external DDR memory on Spartan 3E


Hello.....

First of all a question. When you say that you created a test project that tests the DDR SDRAM, are you referring to the auto-generated project form the EDK when you infer the DDR controller or this is you own custom made project?
If the answer is that you use the auto-generated project then the fact that it freezes may show a lot of things:
Do you use a custom made board or you bought one? (just thinking of bad external memory connections but not probable)
Does you project meets timing? It is very crucial for the good functionality of the DDR Controller. Check you clocks and DCMs.
Check your ucf file for the pins connected to the DDR.
Does the project that you use tests other devices, except external DDR?

Maybe I will think something else latter....

George

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Visitor gir2004
Visitor
14,412 Views
Registered: ‎12-18-2007

Re: help in using microblaze with external DDR memory on Spartan 3E

Hello George,
 
I am referring to the autogenerated project from the EDK for testing the memory. The board I'm using is made by Xilinx and is identified by the EDK. It uses the Spartan 3E (XC3S500E FPGA). It has a 50MHz on board clock. From what I have seen somewhere I'm suspecting that the DDR SDRAM runs at double the clock speed than the OPB bus but I'm not sure how to check if the controller is getting the right clock speed. The project tests only the DDR memory and no other devices.
 
Thanks,
 
Girma
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Observer svenand
Observer
14,402 Views
Registered: ‎08-13-2007

Re: help in using microblaze with external DDR memory on Spartan 3E

I have used the MicroBlaze with external DDR SDRAM on a Virtex-4 board. You can
find out more by reading my blog: http://svenand.blogdrive.com/archive/48.html

Sven
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Xilinx Employee
Xilinx Employee
14,368 Views
Registered: ‎08-15-2007

Re: help in using microblaze with external DDR memory on Spartan 3E

Girma,


Check out the following solution records, this is most likely the cause of your troubles.

http://www.xilinx.com/support/answers/24015.htm

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Visitor gir2004
Visitor
14,317 Views
Registered: ‎12-18-2007

Re: help in using microblaze with external DDR memory on Spartan 3E

Hi Chadn,
 
I took a vacation from my problems and here I found the solution when I get back. After updating the system.ucf file according to the information provided in the second solution record I was able to get it to work. Thanks for your information, I really appreciate it!
 
Girma
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14,287 Views
Registered: ‎01-02-2008

Re: help in using microblaze with external DDR memory on Spartan 3E

hi,
   I am using Generic SDRAM controller for micron SDRAM and faced and facing almost same issues. I also stuk on system halt issue (due to wrong pin assignment), DCM implementaion (for generating 100Mhz clk) and many others. But still I am in problem and when I write data on SDRAM using xmd, and read back same locations, Data at 1st and 3rd byte appear (same at both) and 2nd and 4th byte misses.
 
I am using Custom Board BSB and my hardware is already tested with my SDRAM controller (using ISE, in Verilog). I used ossiloscope to verify clock and will try EDK simulator soon ... can you suggest some thing
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14,201 Views
Registered: ‎01-02-2008

Re: help in using microblaze with external DDR memory on Spartan 3E

my SDRAM is of 16-bit data width.
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