I've gotten to meet many of the key KiCad developers. I just had a chance to chat with Drew Fustini of OSH Park. I've met many people who use KiCad both professionally and as a hobbyist. I got a tour of mHub, a fascinating manufacturing incubator facility.
When Chris Gammell suggested having a KiCad conference, no one thought it'd be as popular as it is. Attendees are here from all over the US, from Europe, and a few people have come from as far as Australia. They hit maximum registration of 220 (limited by mHub's facilities) a few weeks ago and have been turning away potential attendees.
What's the worst thing that's happened? There's a frelling Winter Weather Warning for 3 to 8 inches of snow this afternoon and evening. The picture above doesn't show it well, but it was already snowing at mid-day. By evening the snow was mixed with ice pellets and the wind was blowing it at a 45 degree angle to the ground. Not nice weather for late April. I brought a winter coat and a light sweatshirt, but if I'd known I was going to have to slog through snow I'd have brought my winter boots and some long underwear. Bleagh.
There's some talk of having a KiCon in 2020, and the immediate suggestion was to have it in Europe. My passport has been collecting dust for a couple of years; I could get behind that!
Hi Reece,
ReplyDeleteI am suffering of the same 4004 insanity. I am planning to build a prototype of the address register including incrementer and refresh. Would you share your eagle schematics with me?
As transmission gate devices I might have an alternative: analog switches like SN74AUC1G66. Require power supply but that's available anyway and they are cheap.
Cheers,
Daniel
Follow the link to my OpenCores project. Browse the SVN repository and look in "mcs-4/trunk/pcb/4004-master/". The file 4004-master.sch is an Eagle 6.2 schematic for the entire CPU, while 4004-master.pdf is a PDF rendering of the same schematic.
DeleteI took a look at the SN74AUC1G66 datasheet. It looks like it might well do the job. However, this device is optimized for signals in the 1.65V to 1.95V range, which I'd be a bit uneasy about. I'd probably opt for the SN74LVC1G66 part, which will work up to 5.5V.
DeleteIf you're going to experiment with these things, I suggest building a one-bit DRAM cell driven by the microprocessor of your choice. The entire i4004 design, from the Instruction Pointer to the (non-existent) OPR and OPA registers, is dynamic logic. Nothing but charges on component inputs and outputs that keep their values long enough for the next cycle to refresh or change them. If you can get a DRAM cell to work with a slow refresh rate using these parts then you may have a fighting chance to make the rest work.