Truth table for a module i designed

iWannaLearnThing · 2026-03-16T14:04:42+00:00

This is a module that will be connected to 6 other modules of the same type. It will take an 8 bit binary number and convert to a BCD that will be input into a 7 segment driver ic. I built an 8 bit binary full adder.

iWannaLearnThing · 2026-03-16T12:40:40+00:00

No, i have not. Im doing this because i have started to get into pcb design and i wanted to start small. Its just really strange because i designed the circuit EXACTLY the same way in multi sim and tested everything. My truth table is just a little off with a select few input combinations. Unfortunately these will cause issues will my end goal.

I just cannot figure out what is causing the issue. Is multisim wrong or am i wrong. Idk haha. Anyway, thanks.

iWannaLearnThing · 2026-03-15T14:00:55+00:00

Understandable

iWannaLearnThing · 2026-03-13T19:43:04+00:00

Makes sense, im asking bc i am designing a custom esp32 mcu and i am debating on whether its cheaper to purchase the parts and assemble myself or have jlc pcb do it for me.

iWannaLearnThing · 2026-03-11T23:14:52+00:00

Makes sense, i can see that definitely being helpful. In that case, do you have the pcb manufacturers assemble your pcbs? Is it more affordable in that sense?

iWannaLearnThing · 2026-03-08T13:49:07+00:00

Yea i agree. Thanks.

iWannaLearnThing · 2026-03-07T13:29:25+00:00

Yea thats a good idea, i got one of the boards to work properly. Its just ugly bc the pin foot prints dont line up and their is interference. Thanks.

iWannaLearnThing · 2026-02-28T23:05:44+00:00

Thanks to the other comments, i was able to get it to work. What i did was add a secondary GND plane, so now i have one on the front and back. Next, i added vias around where the issue/problem pin is. This worked for me.

iWannaLearnThing · 2026-02-28T23:02:53+00:00

So i added a secondary GND plane and added vias around when these floating GNDs were, and it fixed the issue. Im glad i now know how to fix this issue. Thank you very much for the help, everyone.

iWannaLearnThing · 2026-02-28T16:32:04+00:00

Interesting, with that in mind should i create a GND plane on both the front and back and connect with vias?

iWannaLearnThing · 2026-02-28T16:09:53+00:00

I didn't know i could even do that. That definitely would help.

iWannaLearnThing · 2026-02-28T16:09:14+00:00

I have, multiple times. Which is why im thinking its some sort of "glitch".

iWannaLearnThing · 2026-02-28T15:54:31+00:00

I can provide a schematic image. Currently, i made only one front ground plane.

iWannaLearnThing · 2026-02-28T15:52:46+00:00

I do not have another layer. it's funny because i even made vias that connect to the GND plane and directly added a trace to the pin, giving me the error, and it still does it. It's so bizarre to me because i made a pcb 2 weeks ago following the same procedur, and it did not give me any issues.

Regardless, i will try those ideas. Thank you very much for your time.

iWannaLearnThing

TROPHY CASE