I'm an embedded software type who has suddenly gotten a strong urge to learn about FPGAs and VHDL. I've done a fair amount of hardware design in the past, but only using standard micros, peripherals, 74xx stuff, etc. I've looked at some beginner threads, but I have some questions that I did not see answers to. I know these are vague questions, but they're the best I can come up with for now:1) I know I want to learn VHDL. I know this (or at least, I think I know this) because I've used C a whole lot, and Ada a little, and I vastly prefer Ada. I read a comment here that while Verilog may be used more in the US for ASICs, VHDL is used more for FPGAs. If true, why is this?
2) Where do I get a free VHDL compiler? Does it come with the free tools from Xilinx and/or Altera? Or do those free tools simply work with other vendors' compilers? The whole tool situation is completely confusing to me.3) For my situation, where ease of learning and a cheap but capable evaluation board are the important considerations, which company's free tools and which evaluation board should I get?
4) I'd also like to find what I guess I'd call prototyping boards, with my meaning of the difference being that an evaluation board would have enough hardware to make for a reasonable development environment, while a prototyping board would be a cheaper and smaller board using the same FPGA for one-off or very low volume projects.5) Is it a fairly simple process to download VHDL modules floating about on the web and incorporate them? I am particularly fascinated by the notion of downloading a CPU core and building some goodies around it.
6) Eventually I'd like to learn enough to be able to design a simple CPU core. Is this a reasonable goal for an after-work "hobby"? How big are e.g. 8-bit CPUs like the 6811, Z80, AVR, etc, in lines of code, and FPGA real estate? (measured in gates? is that the standard unit of chip real estate?)
Thanks for any answers or suggestions!