15 Jun
2008
15 Jun
'08
7:36 p.m.
Andrew Lynch wrote:
As for low cost EDA tools, have you tried KiCad and
FreeRouting.net? There
are links on the N8VEM website: http://groups.google.com/group/n8vem
Originally, I designed the N8VEM SBC on notebook paper by hand. Later I
recaptured the design with KiCad and used the FreeRouting.net
autorouter/manual router.
I like quad paper myself ... 3 AM I don't want to turn on the puter...
The N8VEM hardware documentation is done using
KiCad/FreeRouting.net to
create schematics, PCB layout, Gerber files, drill files, BOM, netlist, etc.
KiCad is free (beer, speech) and FreeRouting.net is free (beer).
They do a great job of schematic capture, PCB layout, have fairly complete
parts library, have the ability to make custom parts, and do a great job of
both autorouting and/or manual routing of PCB traces. Total cost $0.
I decided to order DIP-TRACE 2K pins @ $500 US.
The problem with the free software I was using was I had logic pinouts
but no POWER/GND signals. This project looks to have several
8" x 10" boards and of course the traditional front panel - LEDS and
SWITCHES.
Since I only have about 20 switches this will be a 16 bit CPU with a 1 MHZ
memory cycle and built in D-RAM refresh for 18 address lines.
The MMU is the only sticky part in my design so far with 16K code/data
pages. Default 64K address space with 4K I/O page.
I doubt you'll find a 4 bit wide bit slice CPU
(AMD2901) in the KiCad parts
library. That part is a bit obscure these days. However, it'd probably be
easy to do a custom part model since it is a plain 40 pin DIP with normal
IO.
The EEPROM is probably a 2816 or similar and is already in the extended
parts library.
I think my first project will be a simple EEPROM programmer.
Thanks and good luck with your project!
Andrew Lynch