02-01-2012 05:37 PM
I am a complete beginner when it comes to working with this board. Could someone please explain how I would be able to read in values from the VHDCI connector on the Atlys Spartan-6 Development Board? I have installed Digilent Adept, and after scouring the reference manual, found out that the VHDCI reads values into I/O bank 2. What is a simple test program that could read the value (high or low) from a single pin on the VHDCI connector?
Thanks so much!
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02-01-2012 06:24 PM
The VHDCI connector I/Os are no different to, say, the switches or buttons. You could do something like this:
assign led_0 = vhdci_0;
You'd just need to make sure you have the pin constraints set correctly in your UCF.
02-01-2012 10:18 PM
Thank you! This is exactly the sort of advice I was looking for. I downloaded Xilinx's ISE, and am attempting to write my first program. Could you give me any further information on setting the pin constraints in my UCF? Not exactly sure what that means.
02-01-2012 10:49 PM
If you're new to Xilinx ISE and HDL design in general, I recommend that you work through the examples in the ISE In-Depth Tutorial. You can probably skip the schematic-based design chapter unless you need to support legacy designs, and ignore the fact that it's written for ISE 12.1 if you're using something later.
Pin constraints are covered in Design Implementation, but it'll be well worth your time to work through all of the examples in addition to thinking about your own design problem. The tutorial covers a few key concepts like using CORE Generator, which you'll need to know for any serious project.
02-01-2012 11:23 PM
I am reading through the tutorial right now. However, for my scope of the project I really don't need to know a whole lot about programming this guy. My main concern is simply being able to test that the FPGA is reading in the correct values from the VHDCI connector.
That said, when writing a basic test program (The one you described above where a port is read in and output sent to LED is perfect), how many files would be necessary? It sounds like a verilog and UCF file are required, but are there any others for a barebones test?
02-01-2012 11:36 PM
Now that's the kind of easy project I wish I was doing!
You'll only need one Verilog file and one UCF. Digilent supply a sample UCF at the Atlys page ("Master UCF File for Atlys") that you can copy the appropriate lines for your input and LED (or comment out all the lines you don't need - if you have extra nets defined in the UCF that you're not using in the top module, the tools will complain)
02-02-2012 12:14 AM
Awesome! I've downloaded the UCF from the digilent page and am tweaking it to my liking right now. Thanks so much for your help! I'm sure I'll have more questions in the future :)