FPGA Verification - how to give input bits and get output

[rd15]

FPGA Verification!

Hello all,

I am a first time FPGA user. I have programmed a Xilinx FPGA using VHDL and now want to use this FPGA for practical purposes. I do not know how to do that. How will we give input bits and how will we get output?

Thanks...

 

[Marcel Majoor]

Re: FPGA Verification!

The 'outside' world for VHDL code is the 'entity' declaration in the top part of your (top level) design. You define here the input and outputs.
At that point the input/outputs are defined, but it is yet unknown on what, physical, pins they are located on the FPGA. This is defined by a constraints file. This file typically has the .ucf extension. This file contains pinnames and there physical location. It typically also contains not only the name of the clock pin (which should also be part of your 'entity'), but also the 'timing' of that clock pin (how long on, off, ...).
When using the Xilinx ISE you can have the ISE 'generate' this constraints file for you (Pace/Floorplanner).

 

[rd15]

Re: FPGA Verification!

I think you didn't get me. I have already programmed FPGA using ISE Webpack software. Now I actually want to use this FPGA for working.

Thanks...

 

[Tan]

Re: FPGA Verification!

Hello all,

I am a first time FPGA user. I have programmed a Xilinx FPGA using VHDL and now want to use this FPGA for practical purposes. I do not know how to do that. How will we give input bits and how will we get output?

Thanks...

Hi,
Read the datasheet of the FPGA you want to work on.Generally output pins are led's,lcd display,or if any UART output.And input pins will be switches(dip switches) or simple switches.
To try a simple program,give the input to the dip switches and write the condition in such a way that whenever you get input to switches output must be displayed through leds.

For complex programs,like ethernet etc..input and output will be clearly in the datasheet.You can follow that.
Hope I am clear..ALl the best..

 

[Marcel Majoor]

Re: FPGA Verification!

Using a LED as output, and acting on a digital input is the most basic application you could implement.
If you are looking for some 'communication' with the outside world, then a RS232 interface is probably one of the easiest to implement (both in software and hardware).
For the software have a look at this post:

The hardware would be a simple RS232 driver/receiver, like the MAX233.