[EMAIL PROTECTED] wrote: > I have used Protel PLD to create GALs with much success, but then I had > used CUPL for that purpose in the past.. I do not like PLDs created in > schematic capture and my experience trying to support the ones I inherited > that were done in schematic capture has led me to conclude that it is a big > mistake.
Well, there are certainly a lot of people on your side, but schematics still make more sense to me. > > With Xilinx you have to be careful what library items you use and make sure > that the correct XNF for the library items are used by the Xilinx tool. If > this is a current Xilinx part supported by the current Xilinx tools I would > use VHDL or Verilog to create the source files than use the Xilinx tool to > compile it. When designing DSP filters or highly numerical circuits, then the HDL makes a lot of sense. When things are highly repetitive, HDL also makes things easier. I do a lot of control logic, bus interfaces, etc. and a schematic just is much faster to glance at and see the area where one is concentrating one's interest at the moment. I just finished a design that pretty much fills a Spartan XCS30 (30K gate) array. It has a bus interface, 4 24-bit quadrature encoder counters, 4 24-bit programmable rate generators with some extra logic to adjust setup and hold times at the outputs, and some digital I/O pins. This all fits on about 5 sheets of schematics. The Xilinx- generated VHDL runs on for 50+ pages. Hand-coded VHDL would be shorter, of course, but I think still more cryptic than the schematics. This is not true on all projects, but for me, I prefer it this way. A recent project had 48-bit binary to Gray code and Gray code to binary converters. I did these in VHDL, as it was a LOT more concise (about 8 lines each). I then created schematic symbols from these VHDL modules and put them on the schematic sheet. I am using Xilinx Foundation for this, as I just couldn't get Protel to handle Xilinx parts properly. I really prefer the schematic editor and the simulator in Protel, they are a lot more user friendly and intuitive that Xilinx, but the back-end would not work for Xilinx parts. Jon * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * To post a message: mailto:[EMAIL PROTECTED] * * To leave this list visit: * http://www.techservinc.com/protelusers/leave.html * * Contact the list manager: * mailto:[EMAIL PROTECTED] * * Forum Guidelines Rules: * http://www.techservinc.com/protelusers/forumrules.html * * Browse or Search previous postings: * http://www.mail-archive.com/[email protected] * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
