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Honored Contributor I

Accessing Data on the FPGA or SDRAM from a PC

I am using a DSP Dev. Kit, Cyclone III Edition:  


In order to verify my system and to test the idea behind the prototype I would like to access data stored on the FPGA as well as on the DDR2 SDRAM. Ideally I would like to sample about 40MB with the ADC, store in the SDRAM and access through USB from a PC. On the PC I would like to play with that data by using Matlab/Octave.  


What is the easiest way to do this? If there are workarounds I would also be happy to learn about these.  


Thanks in advance for any help!
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Honored Contributor I

For small chunks of data(not 40MB) a workaround is to use signaltap to capture data then store it in pc. 

I believe DSP builder got a function for that or you can do that manually as follows: 


set all signaltap data to signed values. then right click mouse and tick generate text file. 


remove all header iinformation from text file to leave the data only. 

then in matlab load your file: 

load filename.txt 


this genertes a matrix called filename 


then choose the data e.g. 

data1 = filename(:,1); all rows of column 1 and process it... 


You may be able to trigger the signaltap at various points of time to concatenate into larger data set.
Honored Contributor I

Thank you!  

Did I see that correctly that Signaltap's data length is limited to 128k Samples? Therefore, if I want to transfer more data, I need to build a USB-interface?  

Thanks in advance for further advice!