- Thu, 2013-08-29 12:41
- 0 Comments
In the spirit of Open Source Hardware I have been using another common CAD product but found that I was spending lots of time doing the same motions repeatedly whereas I am big on automation in the form of auto-labeling and single click repeats.
I have been using CAD system since there were no CAD systems, we literally drew the schematic twice for the C128 back at Commodore Business Machines in the 1980’s; once on grid paper and then again on a frightfully expensive dedicated Mentor workstation that up until then had been used to do chip design. To this day I tend to select the colors we used on the Mentor though I no longer grow a pointing fingernail on my index finger for operation of the “scratch pad” touch controller.
So fair to say that I am accustomed to a professional level of tools where workflow and repeatability are highly desired. The problem with the tools I tend to like is the cost; look at Orcad or Altium and it’s a couple of thousand to get started and that’s for partial packages. So no small wonder that Eagle has gotten the tremendous following it has in the hobbyist community, they offer home users a stripped down package that allows one schematic sheet and a small 2 layer PCB for only $69. For a slightly better version the cost is $169.
So here's the good news; a full blown Cad system is available for $249 which includes a professional Schematic Entry program which is a great time saver and the PCB Layout is less like drawing and more like routing; in fact I dropped a design in the autorouter that Eagle could not get routed after a day of massaging, and the design was 100% routed by the time I got back with a cup of coffee. I ran it again just to watch the process and my CPLD Arduino Shield (more on that later) and it was done in less than 2 minutes albeit I do need to tweak the power runs, but the message is that it can not only do what had been a complicated layout, it did it easily leaving little doubt that I could make lots of changes without endangering the ability to complete a design. For $249 the only real restraint is that the design is limited to a maximum of 500 Nets, I am told that the upgrade path costs the same if you grow your way up to bigger designs or purchase a higher level outright.
Note that I did not even get into simulation yet, I will post some example down the road of basic simulation and then full processor state simulation from ROM code.
Now mind you if you need a full blown professional PCB layout done, with things like correctly done constant impedance, all of the applicable specs met, and your parts correctly footprinted I go to my friend Terry Fisher at Fisher PCB who I worked with in the 1970’s then again at Commodore… we got used to slam-dunking our FCC submissions as he is as good at his craft as I am at mine.