Transfer RAM content to computer

Altera_Forum · ‎10-11-2011

Hi,

I use the Altera board DE2-115 with a cyclone iv chip to produce data. I can store this data onto the RAM of the board.

The next step I can't handle is to transfer this data from the RAM to my PC to analyze it. I am unable to program the NIOS II processor to read the RAM and transfer it via USB or Ethernet to my computer.

Does anybody have code to transfer the whole RAM content (best would be the 128MB SDRAM) to the PC via USB or Ethernet?

That would be a great help. Thank you!

Regards, David

Altera_Forum · ‎10-11-2011

Assuming you don't care if it takes a long time to transfer the data you can try HostFS (Host file system). Using HostFS you can open, write, read, and modify files located on your host system from the FPGA (containing Nios II). It works over the debug channel to move data back and forth to the host. You can find more info here: http://www.alterawiki.com/wiki/host_file_system I haven't used it in a long time but I seem to recall getting around 4.3 KB/s speed with in. So if you want to try it out I recommend experimenting with small files first. Another method would be to use System Console to pull the contents out of the FPGA and funnel the data into a file on the host. If you search around you'll find various ways to do this.

Altera_Forum · ‎10-12-2011

Thank you! I will try to get this to work.

Still it will take the whole night to read out the RAM. Therefore something faster would be better.

David

Altera_Forum · ‎10-12-2011

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Still it will take the whole night to read out the RAM. Therefore something faster would be better.

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Your options on the DE115 are;

1) JTAG USB; max speed is about 6MHz/10 per byte, i.e., 0.6MB/s

2) USB; the ISP1362 is a full-speed device, so 12Mbps/8 = 1.5MB/s at 100% USB bus bandwidth (unlikely you'd ever get that).

3) GbE; 1000Mbps/8 = 125MB/s at 100% utilitization ... I think 80MB/s is probably about the max you'd get.

4) Use an FTDI FT2232H on the GPIO connector; 25MB/s (according to their data sheet).

Use (3) and you can transfer your RAM contents in a few seconds.

Cheers,

Dave

Altera_Forum · ‎10-13-2011

I agree... Ethernet should be the way to go if you need speed.