Hardware vs Simh (and FPGA)

On Apr 24, 2013, at 7:32 PM, ben wrote: Well, "easy". Hardware description languages have a steep learning curve. If you're just starting out on them, it's probably helpful to remember that what you're doing is a lot more like describing a schematic in text (much like a SPICE netlist, though with some more "programmy" bits) than programming in a language like C. If you have some template code you're planning on working with, that's probably a good start (there are lots of CPU projects on opencores.org, as well as a lot of other cores for interfaces like SPI if you need them). This is a good reference for programming in Verilog that I used when I was learning (and still come across helpful sections when I'm Googling for usage details on the more obscure parts). It starts from a beginning level. http://www.asic-world.com/verilog/veritut.html This is a great quick-reference card to print out and stick to your wall. http://www.ece.uvic.ca/~fayez/courses/ceng465/vlogref.pdf For a Verilog simulator, I highly recommend Icarus Verilog, which is a nice open-source simulator with quite a bit of support. http://iverilog.icarus.com/ Of course, if you want to do VHDL (Sytse's implementation is done in VHDL, so that might not be a bad jumping-off point), there are similar tutorials. Google for them. GHDL is the main open-source simulator that I'm aware of, but I haven't used it much; I tend to stick with Verilog for my own projects because I like Icarus a lot. VHDL has the benefit of being much less limiting down the road compared to Verilog (without SystemVerilog features, most of which Icarus doesn't support, you can't even make a proper linked list because there's no dynamic sizing or allocation of ANYTHING), but I feel like it has a steeper learning curve partly because it's so type-strict (which, once you get the hang of it, is really more of a benefit because it doesn't tolerate much ambiguity). For tools for building the FPGA, just go to altera.com and download the toolchain (the free "Web Edition") for your platform. The Linux tools and the Windows tools are both equally good these days. If you want any help, advice, etc. on FPGA stuff, feel free to email me; I do it professionally in both VHDL and Verilog with both Xilinx and Altera FPGAs on a regular basis. Sure. It's great for small, CPLD-sized things. You'll probably not like it so much for building anything big. - Dave