I want to learn VHDL but I really don't know from where to start.
I want some advice and explanation about the software I need to get started.
I would like also to get some references in order to learn it efficiently without wasting time by searching on the Internet, since there are a lot of e-books and tutorials and I'm really confused about which one to choose.
I suggest, you have good background in Digital Design. If not, start with any edition of "Digital Design" book or, alternatively "Contemporary logic design".
Download GHDL (VHDL compiler/simulator using GCC technology) or a little more friendly software tool boot.
Learn how to build a VHDL program with GHDL. Try to compile simple "Hello, world!".
As others have said, you need to learn about digital design before learning VHDL. But don't let that scare you away, it isn't that hard. I believe you can get started very fast with VHDL if you get the books, board and software which I recommend below.
"Digital Design" by Frank Vahid is an excellent book for people who wants to learn about digital design from scratch. We used that book in an introduction course on digital design where we also got introduced to VHDL. You don't have to dig very deep into that book before you can start playing a bit with VHDL (this book doesn't teach any VHDL though).
I remember the book as being very 'reader-friendly'.
http://www.amazon.com/dp/0470044373/?tag=stackoverfl08-20
Next you really need to buy or have access to a FPGA board, and some learning material that utilizes and explains about that particular FPGA board that you choose.
Even though I had access to a FPGA board at my university, I choose to buy a board so I also could play around with VHDL at home.
At university we used some virtex-pro Spartan-3E 100 MHz board (can't remember the exact name). And for home I bought the Nexys2 board which is also in the spartan-3E family, and is an excellent board for FPGA beginners IMO.
http://www.digilentinc.com/Products/Detail.cfm?Prod=NEXYS2
For VHDL we used the book "FPGA prototyping by VHDL examples" by Pong P. Chu, which is an excellent book for getting some experience with VHDL fast without having to read too many boring pages.
The book also introduce you to the 'Xillinx ISE' software.
http://www.amazon.com/FPGA-Prototyping-VHDL-Examples-Spartan-3/dp/0470185317
For software we used Xillinx ISE, compatible with both Linux and Windows (I used it mostly in Linux). At university we used some old version of Xillinx ISE because the new version wasn't compatible with the virtex pro board. This was the worst piece of software I've ever used, it was full of bugs and it was driving everyone crazy!
BUT at home and on my laptop I used the newest version of Xillinx ISE which was a brilliant piece of software, and didn't have any annoying bugs. The only thing I didn't use Xillinx ISE for, was to transfer the synthesized VHDL (.bit files) to my board, for that I just used 'Digilent Adept software' (some small program made by Digilent, for transferring files to and testing the board). But it should also be possible to set up Xillinx to be able to transfer the synthesized VHDL, if you aren't lazy like me.
So if you want to use Xillinx ISE, be sure to buy a board that is compatible with the newer version of Xillinx ISE, to avoid too many head-aches. For example the Nexys2 board.
We also used some nifty tool for debugging, think it was ModelSim. This should also be included in the Xillinx ISE webpack download if I'm not wrong.
Link to Xillinx ISE:
http://www.xilinx.com/ise/logic_design_prod/webpack_faq.htm#2b
I am in a very similar situation. I discovered Free Range VHDL and am learning fast as I work through it. This book is an update of The Low-Carb VHDL Tutorial with exercises at the end of every chapter.
After completing the paper exercises, I plan to get an XuLA board from XESS. Dave Vandenbout has written an excellent tutorial referencing his XuLA board. This book complements Free Range VHDL as it discusses actual FPGA devices and practical issues such compilation, synthesis and software download. This book is also available from the Free Range Factory and I have found an earlier edition on this pdf.
Dave Vandenbout's site offers more hardware than the Free Range Factory, so it is worth checking out. I am based in Europe, so I will also be looking at Trenz Elektronik online shop.
The web page for the first part of this course (more specifically, the course literature, tools and links parts) contains a pretty good list of reading material and tools. The course doesn't offer any introduction to VHDL but is open to students with no prior VHDL experience even so, so learning on your own with the provided material works pretty well. (At least it did for me; YMMV.)
