Mostly interested in how all of those components are actually put together at the transistor level. Yes it's cheating to get a kit with discrete logic just like it's cheating to get one with a microcontroller. The difference is if you give me a microcontroller I already know how to program one of those. What I don't know is how to build one from scratch.
I guess I could see what assembly the sketch or app would compile to and then try to track down what each asm instruction translates down to in terms of transistors, but a bottom up approach seems to be a better learning excersize. For instance, I wouldn't mind finding a display driver, a ALU and etc as chips in a kit. On the other hand I don't think I would want to try my hand at implementing a calculator from logic gates built from transistors & diodes. One possibility would be building each of the components from ic gates instead of purpose built discrete components. However the real question is where to start on this. I get basic gates from transistors. I have a forest mims book on digital logic controllers and I do have a handful of ic's in hand from the kit that came with that book. However the book didn't seem to go in any general direction even though the kit was really high quality. Just sayin, a programmable microcontroller seems like overkill. What did they do back in the days before $0.25 PICs? On Thu, Jul 11, 2013 at 3:49 PM, Levi Pearson <[email protected]> wrote: > On Thu, Jul 11, 2013 at 1:57 PM, S. Dale Morrey <[email protected]> > wrote: > > My birthday is coming up in a month and my wife asked me what I want. > > I decided I want to go really bare metal and build my own pocket > calculator. > > I found this kit... > > > http://www.spikenzielabs.com/Catalog/index.php?main_page=product_info&products_id=762 > > > > The only problem I see is that it's using a programmable microcontroller. > > That sort of feels like cheating. I'd prefer to build one from discrete > > logic units, even if the result would be big, bulky and slow. I just > want > > to geek out and learn something in the process. > > > > Does anyone know of a calculator kit or project using discrete logic? > > > > Thanks! > > If you are doing this as a circuit assembly/soldering exercise, it > doesn't matter whether your ICs contain discrete logic elements or > little microcontrollers. If you are doing it to learn something about > how a calculator works, isn't it also cheating to get a kit that tells > you how to wire discrete logic elements into a calculator? > > What you need is an introductory digital logic book or web page, a > variety of logic ICs in DIP format, a keypad, a 7-segment display, a > good-sized breadboard, some wire, and miscellaneous > resistors/capacitors/etc. required to safely hook them all together. > All of which are likely to be found at any number of electronic > hobbyist stores. > > Now, learn to build an adder from NAND gates. Learn how to combine > adders to implement the basic arithmetic operations. Learn how to > build a flip-flop from NAND gates, and how to build a memory register > from flip-flops. Learn how to combine them all into a basic > calculator. > > After you have the logic figured out, you need to learn the messy > analog bits that are still required to debounce buttons and power > digital circuits. Fortunately these are pretty simple as far as > analog circuits go. > > Now you plug all your components into the breadboard, hook them up > correctly with jumper wires, and scratch your head and replace > burnt-out components as you try to figure out what you did wrong. > > Finally, once you get it all working, you can lay out a circuit board > and etch it and solder all your components on and go through a couple > more head-scratching iterations until you have a working calculator! > > Or, you could just buy the kit and have a cool gadget sitting on your > desk. How much time do you want to devote to this? :) > > --Levi > > /* > PLUG: http://plug.org, #utah on irc.freenode.net > Unsubscribe: http://plug.org/mailman/options/plug > Don't fear the penguin. > */ > /* PLUG: http://plug.org, #utah on irc.freenode.net Unsubscribe: http://plug.org/mailman/options/plug Don't fear the penguin. */
