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What sort of simulator is required to go from “running” to ordering a prototype board 26 days later? I had assumed physical breadboards and wires and chips wer
by WalterGR 6y ago
What sort of simulator is required to go from “running” to ordering a prototype board 26 days later?
I had assumed physical breadboards and wires and chips were always necessary to prototype...
2019-11-02 The first version of the MyNOR simulator is running. The circuit works!
2019-11-17 I have finished the work on the microcode. I added support for MyNOR to my cross-assembler myca.
2019-11-28 PCB layout completed. A friend told me about JLCPCB, so I ordered the prototype board there.
- pjc50 6y agoProfessionals generally have enough confidence to go straight to PCB. Solderless breadboards have enough capacitance that they aren't suitable for high-speed digital logic anyway.
- progre 6y agoThe simulation tool for Altera FPGA:s was pretty powerful when I used it a few years back. You'd basically drag and drop "packages" like the 74xx components, connect them and you could run the circuit with timing profiles and all. The purpose is of course not to actually then build it out of discrete logic but to synthesize it to a FPGA bit stream, but once you have the tool setup (it required something like 200 gigs if disc space and was extremely picky about drivers) I can see it being an option for this sort of thing.
- rcxdude 6y agoNope. I design electronics professionally and I rarely do breadboard prototypes (and almost never using a solderless breadboard). This is because I can be reasonably confident about the behaviour of most circuits with perhaps a little bit of simulation using a SPICE model for some analogue parts. For complex digital logic (which is very rare to design using seperate ICs these days, you would use an FPGA) there is a multitude of simulation systems you can use as well to test your design (including some of the design tools for FPGAs). PCBs can be made cheaply and on short notices these days (I can get 5-off a 4-layer PCB for $200 in 4 days, and that extends both cheaper if I can wait longer and shorter if I want to pay more), and solderless breadboards are atrocious for almost anything I'd want to prototype (the parasitic capacitances, inductances, and resistances are all really bad. sensitive analog circuits, high-speed digital, and power electronics all suffer badly from those).
- colejohnson66 6y agoIn fact, it can go down to about $5 and shipping with places like JLCPCB if you can handle only 2 layers at a maximum of 100x100mm
- jacquesm 6y agoSolderless breadboards are the equivalent of exploratory programming. If you know what you want to make you might as well go for a PCB (you can simulate the logic quite nicely these days).
- varispeed 6y agoThis doesn't work for high speed designs though. Probably anything over 20MHz will be difficult to make useful on a breadboard.
- jacquesm 6y agoTrue, the parasitic capacitance of those boards is horrible. Personally I wouldn't even try to go over 5 or so, but that leaves room for plenty of interesting and educational projects.
- antoinealb 6y agoWhen I was in university, we used Logisim[0] for our intro to digital logic class. I think you could probably simulate such a computer in this tool if you wanted something intuitive. Otherwise you can prepare your design in a high level logic language like Verilog and test it using Verilator [1]. Naturally there is always a risk when going from running in a simulator to the real PCB. [0] http://www.cburch.com/logisim/ http://www.cburch.com/logisim/ [1] https://www.veripool.org/wiki/verilator https://www.veripool.org/wiki/verilator
- eat_veggies 6y agoOne of my favorite assignments in college was building a little ALU in Logisim :)