gEDA-user: CPLDs and other high-density logic chips...

[John Sheahan]

Samuel A. Falvo II wrote:
> I am working on a project that, in the end, may require me to utilize
> a CPLD just to get the thing working and cost-effective.  But I really
> have no knowledge of how to prototype with such beasts.
> 
> Is there a body of resources that you folks would recommend to a
> *total* neophyte with respect to CPLDs and FPGAs?  The farthest I've
> gotten in Verilog was to actually get something to simulate via
> Icarus, but actual synthesis and resynthesis is something that still
> escapes me, unfortunately.

you probably want to choose either Xilinx or Altera for a start.
Both make good things.

once that choice is made, visit their web site for docs.

if you have code that simulates, you need to add a file mapping IO's
to pins, a wrapper instantiating IO drivers, and you are pretty much done.

For example, if you were to pick xilinx, and with what you have 
mentioned, you might want to drop the cpld, put a small spartan device 
on the board, and add a configuration device for that.

your tool budget is then just a programmer for the configuration device.
icarus and the web tools will do the rest.

> 
> Also, what kind of capital investment am I looking at?
> 
> My plan was to use a relatively simple CPLD for address decoding and
> other glue logic functions, but also perhaps an FPGA for generating
> VGA (640x480) video.
> 

this would work - but is probably 1 device more than required.
1 is usually easier than 2.
john


> Thanks.
>