Data Transfer To and Fro Digilent's Nexys-2 board

[OhJ]

hello sirs,

I would like to request support from anyone who has much experience and success using Digilent's Nexys2-500/1200 FPGAs.

1) The Nexys board is said to: "Transfer data to and from the onboard FPGA on your system board. Read from and write to specified registers. Load a stream of data to a register or read a stream of data from a register." - as per information from their website.

I have gone through the tutorial titled: Parallel Interface reference design for data transfer between PC and FPGA.
The above is referenced at: http://www.digilentinc.com/Products/Detail.cfm?NavPath=2,66,828&Prod=ADEPT2

My challenge is not being able to write to or read from the board successfully, as far as the tutorial is concerned. For example, the below is the content of my .coe file:

memory_initialization_radix=16;
memory_initialization_vector=
00000400, 000000A1, 00000000, 00000000
00000000, F802F000, F832F000, C830A00C
18243808, 46A2182D, 46AB1E67, 465D4654

with respect to the above tutorial, I can write(upload) the above file.coe using the "write data into memory" write
button on the Memory tab of the Adept software. However when I want to read, I keep getting the error message:

"Error: Length must be a positive integer,
Error: Length must be a positive integer,
Error: Length must be a positive integer

So I cant really verify if what I uploaded is written successfully or if its the reading part of the process that has issues.

Unfortunately too, I havent gotten much support from the people at Digilent. Even with repeated emails, there is no response.

The reason I would require the above reading and writing feature is because I would like to be able to dump data onto the board(registers) - use the data via my design; send the results back into these registers and extract it via the adept software for further analysis.

Or perhaps, if there is a better way of doing such / a work around via commandline, kindly advise

warm regards
OhJ

 

[Lode]

Hi,

I am facing the same problem here. Did you manage to get it working?

regards,
Lode

 

[mrflibble]

I've played with that Adept tool in the past, and then it wasn't working so well. Maybe they fixed it in the meantime, not sure. After all, the digilent jtag plugin was also problematic at first, and current releases work fine. All that to say: this tool you're trying to use was problematic in the past, but maybe (hopefully) they fixed things.

I found it too much hassle for what it offered. If all you want is a quick-n-dirty way to pump data in and out, there's a couple of alternatives:

1 - use the onboard RS232 connection. It's not super fast, but 115200 is fast enough for a lot of things.
2 - use an USB-RS232 dongle. Then you connect the RX/TX to 2 pins on the PMOD connectors and you are good to go
3 - use onboard USB. That's useful if you NEED higher bandwidth.

I use option numero 2 quite often because it easy to do + convenient in usage.

And no doubt on human autopilot you're going: I WANT OPTION 3! because it's cool and hip and has more bandwidth. It's also more work.

With the usb/rs232 dongle you can easily get about .5 MBit/s, usually more. That's enough for lots of things.

What kind of data transfers are you talking about? That would dictate the solutions...

 

[Lode]

Hi,

Thanks for the quick answer.

In the mean time i got also an answer from Digilent:

This is a known issue that has been fixed in an update that is set to be released in the upcoming weeks. Keep an eye on our Adept2 web page:



http://www.digilentinc.com/Products/Detail.cfm?NavPath=2,66,828&Prod=ADEPT2



In the meantime, these work around procedures should work:



1. Click “Flash”

2. Select File To Write

3. Select File To Read

4. Enter Length

5. Write File

6. Read File



-or-



1. After you have written the file, close Adept

2. Reopen Adept

3. Select Read File

4. Enter length

5. Read to file.


So I ll wait for the update, and in the mean time I am only reading the flash with my onboard controller and through RS232.

regards

 

[mrflibble]

Guess it's still ...

I've played with that Adept tool in the past, and then it wasn't working so well.

So I shall persist in not using.

 

[joelby]

Another option that works with the Nexys2 is **broken link removed**, which provides a library for programming and communicating with FPGAs at high speed over the built-in USB device. It works in a way similar to Adept but is much better supported

 

[chat]

can the same thing will work on atlys board ? if i change the ucf constraints accordingly ?

 

[joelby]

Yes, they both have the same Adept-compatible JTAG interface based on the FX2LP.

 

[Lode]

In the mean time the bug is fixed by Digilent. I currently use this version:

===== Digilent Adept =====
Adept System Rev 2.7
Adept Runtime Rev 2.10
Adept Application Rev 2.4.2

 

[mrflibble]

Thanks for the update.