Another UART Module

I’m working on a serial communication module that should bring out I2C, SPI, UART, and JTAG and support the most common voltage levels. Unforturnelty, because of a design error, the level shifting circuit isn’t working. So far, the UART is confirmed working, so that’s a good enough reason to start working on REV2. Eventually, it would be amazing to have a set of modules geared towards electronics/embedded development; I see someone is already working on a Logic Analyzer

There are a few more pictures on the insta


Awesome work! Connector selection is definitely a tricky one for this sort of card. We found a 0.1" pitch connector that just barely fits, that we put on the Microcontroller reference design.


To get a better fit, I dropped to 50mil (1.27mm) pitch; this makes it easier to sandwich the board between the two rows.

I made a bit more progress on the module; I made some board-level repairs and got the indications and level shiting circuitry to work. Now I can change the serial comm level to 5V, 3.3V and 1.8V, and the indicator LED. At this point, revision two looks like a production-level device.

The next big thing I need to work on is creating a configuration tool that will allow me to configure the device and provide a terminal or somthing to use the various communication protocols. That’ll be the hard part for me…

There’s slightly better video on Instagram


Do you have a GitHub repository for the schematics?

I do, but I’m not ready to release it publicly yet, there are still a couple bugs. I will more likely make available pdf of the schematics.

The code will probably be open source when it’s ready.


I hope that is enough for me haha. I am really new to the whole designing own electronics hobby. On the other hand it might be a cool little exercise to turn the PDF into a proper Gerber file.

If your looking for a base project, you should checkout frameworks expansion module repo. If you need any help with the electronics or PCB development feel free to drop me a private message.

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I’ve just finished building the second revision of the module, which is more or less a complete redesign. The original serial bridge wasn’t going to do what I needed, so I’m going the MCU route. The plan is to have all the same functionality as the original module, but the MCU should allow some other nifty features; I’d say this is a pretty similar idea to the Bus Pirate. At this point, the board powers up and accepts firmware. Now I need to write the firmware… again.

I did a little blog post about the general design choices and included the Gitlab link if anyone was interested in helping out or had any suggestions. This is all taking longer than expected since it’s a side project; bear with me.