I couldn't find this information on Google (only tried for a few minutes). I saw the GPL v2 license they use and started thinking. I was just looking into gEDA (at their website). I thought for some reason it was completed but just limitations of the software. As I didn't have enough CPU cycles as it is, I used the LCD refresh cycle as the delay for the button debounce. It worked pretty horribly, but it drove an HD44780 LCD and had four buttons to control its operation that were debounced in software. Reminds me of the other project I was working on, a soft SMPS with AT90S4433.

Alas you have to use what you have to use, and you have to learn it.Īnd yes I'd do the debouncing in software. Of the two GPL schematic capture programs I've used now, I think gEDA is closer to 'professional' but gEDA is also quirky. I didn't specify any values for any of the components either, so it's not like it's a finished product, and I don't think an op amp with one connects is really useful (though I am assuming the use of the programmable internal pullups in the 90S2313/Tiny2313 for the buttons.) For multiplexing you'd connect all the A segments together and then connect to one of the PBx pins through a resistor, say A segments to PB0, B to PB1, etc., then the decimal point to PB7. Normally you'd specify which bits you want to connect to the bus but I didn't do that. Imagine it connected however you want, but you don't short out all the output pins together. The blue bus was a detail I did not fully flush out, but normally the fat wires are buses (meaning, multiple wires in parallel) as a convention.

This was intended to sort of be a possible design solution to the presented problem. Yes it was a kicad schematic I threw together to experiment with how to use it as I've never used it before.

Diptrace vs eagle eevblog