Finished Product

I am very happy with how this project ultimately turned out, and the process was facilitated by PCBWay, who are sponsoring this project. Their PCB ordering process was super straight forward, and my board was reviewed and approved for manufacturing much quicker than I've experienced with other manufactuerers. Additionally, they've had the fastest turnaround delivery time I have personally seen as I received my boards in less than a week from me ordering them. They were very high quality and ultimately made my prototyping and project developing experience much better, you can find their services at pcbway.com. With those boards, I was able to get everything working on the first try. The video below shows the board in action, doing a simple LED blinking demonstration. It also shows how it snaps into a breadboard.

This video shows off the UART capabilities that I designed as a part of the board, with 4 headers dedicated entirely to UART. In this case, an FTDI board (which manages UART to USB Serial) is used to take the raw Tx from the microcontroller and convert it to something readable by the computer via USB. It is showing the messages printed using Serial from the Arduino IDE being sent from the microcontroller to the Serial Monitor in the Arduino IDE.

The full schematic for the board in Altium.

A view of the 2D front view of the PCB in Altium.

A view of the frontside of the PCB in 3D in Altium.

A view of the backside of the PCB in 3D in Altium.

Additionally, here is the BOM for the project.

And the total cost of the project comes out to $3.17.

Using the Device & Test Code

Were you to create a board of your own like this, you'll need to program the device. This needs to be done in a special way. See my Coil Gun project page through that link, as there is a whole section dedicated to programming an ATtiny1614. Beyond that, the board operation is simple, and the pinouts are as seen below:

For the Arduino IDE, reference the single numbers in orange for digital or analog pins when writing code. Note UPDI, the programming pin, on PA0 (pin 11), as well as SDA/SCL on 6/7, and finally RX/TX on 4/5.

Development Documentation

Part 1 - The Idea

The idea for this project, especially considering I already have an ESP32 C3 Dev Board project, was essentially to have a more compact and much cheaper microcontroller dev board as another option. The ESP32 C3 is a very powerful chip, and with that comes a larger size, more cost, and more power consumption. I will be using that chip and its dev board in a lot of my projects, but for certain cases, the ATtiny1614 would do just fine, so having this additional dev board I developed as an option gives me a lot more flexibility. I also, like the ESP32, have experience using ATtiny chips before and know my way around them and their power, so I knew I needed this on a dev board as well.

Part 2 - Schematic Design

To design the schematic for this device, it was quite simple. I have done lots of work with ATtiny microcontrollers even with PCB design before, so I already knew just about all of what I'd need to do. All you need to get an ATtiny chip running peripherally is a 5V line, Ground line, and UPDI line (going to pin PA0 in this case, though this differs between different ATtiny chips, of course). Additionally, a 1 microfarad capacitor across 5V to Ground doesn't hurt. And that's it! With those three drawn to pin headers you can program the device and use it as you please. In my case, of course, I wanted to add some additional features. Namely, I added a 5V LDO (though optional to solder on if not needed), pinouts for all the IO pins of the device, a separate UART and Programming pin header, and finally a power indicator LED and builtin IO LED on the board. The schematic came out as follows:

Part 3 - PCB Layout

As for layout, this process was pretty simple. With the schematic laid out properly, I didn't run into much trouble. I, of course, made sure my pin headers were spaced accordingly for a breadboard. I also added 2 M2 mounting holes to the board, and finally labeled all the pins and header sections. The final PCB came out like this:

Part 4 - Ordering, Soldering, & Testing

Finally, after lots of checking with data sheets and my layout/schematic itself, it was time to order the board. To do so, I ordered my boards through PCBWay, who were kind enough to sponsor my work and this project! They produce high quality boards with quick turn around and delivery time, the quickest I've been able to find. The process to uploading my Gerbers to their site and ordering was super simple, and within minutes my board design had been approved for production. In less than a week, I had the boards in my hand. They all came out great. I then soldered one according to the schematic in Altium, and finally worked on uploading some test code. To do so, I followed the necessary steps to program an ATtiny1614 microcontroller, which are detailed here if you are interested. I ultimately wrote some basic LED blinking test code, which can be found in the Github Repository, right here. Ultimately, my simple test code to blink the LED worked first try! Additionally, I did a UART serial test, seeing if I could see printed serial from the chip on the Serial Monitor of the Arduino IDE on my computer. To do so, I had a seperate FTDI board (necisary for converting UART to USB serial). I attached it to my computer, and plugged the ATtiny board into the FTDI board as shown below:

Additionally, make sure the FTDI voltage level shift pins are set to the 5V side (if your FTDI has the 3.3V option). Now, once plugged into your computer, select its COM port in the Arduino IDE, and open the serial monitor. Once done, serial from the ATtiny (Assuming you programmed it to output / print anything serially) will show up, which is what happened with mine first try. Another big accomplishment. All-in-all, my board design as a whole worked on my first iteration, and I now had a working ATtiny1614 Dev Board of my design to use for prototyping future projects!