14 Apr
2002
14 Apr
'02
10 a.m.
Richard Erlacher wrote:
If you buy a moderately cheap CPLD, e.g. the XILINX
95108, in a PLCC84, it
costs about $20-30 U.S. at DigiKey. Combine that with a socket, ($4 tops) and
a few wirewrap socket pins, ($.10 each) that's another $8.40. Now find a
cheap wirewrap board to which you can solder ... and then use the free
software and build the ~$5 ISP adapter.
Has anybody done that?
For the same money, you can use a
Xilinx SPARTAN-series FPGA which you can also program using the ISP
programmer, though you'll have to do it every time. Then you can design
pretty much whatever small computer (only because of pin-count limitations)
you want. These devices even allow you to put in some RAM.
I have a nice FPGA prototype kit, (altera) but I am having problems
getting A PROM for it. I may go to using smaller chips like the XC-9572
(72 macro cells) ? $12 canadian. They don't make wire wrap PLCC sockets
(or not in DigiKey) so I will end up with making a PCB. I have a new CPU
design and expect about 10 CPLD's in total.
--
Ben Franchuk - Dawn * 12/24 bit cpu *
www.jetnet.ab.ca/users/bfranchuk/index.html