Demonstration Videos

Below are videos demonstrating different features of the ATMega328PB Dev Board.

Programming via SPI & Builtin LED Flash - Demonstration

The video below shows me programming the chip on the board and blinking the builtin LED at different speeds.

MCU UART to USB Serial via FTDI - Demonstration

The video below shows the board outputting MCU UART data through an FTDI board to USB Serial on my laptop.

Final Schematic Design & PCB Layout

Below are photos showcasing the final schematic sections and printed circuit board design for the project.

Entire Schematic

PCB 2D View

PCB 3D View - Front

PCB 3D View - Back

Bill of Materials (BOM)

Below is a table containing all of the parts as well as a link to the Digikey parts list.

Using the Device

Device Pinouts

Below is information and necessary tables of pinouts for the device.

Setting Up & Using the Device

The device can simply be plugged in via any of its power inputs to power it on. This includes the barrel jack input, for VIN, which can take >9V, the USB-C port, or the external 5V in line of the programmer header. As for programming, the device needs to be connected to an SPI programmer. For my case, I used an Arduino Uno. I flashed the Arduino Uno with the "Arduino ISP" example code file that comes with the arduino IDE. From here, I connected the Arduino Uno to my ATMega328PB Dev Board according to the table below:

Once hooking it up as such, make sure the onboard switch of the 328PB board to enable programming mode is in the ON position, i.e. it matches the silk screen indicator. From here, if using the Arduino IDE like me, install the "MiniCore" board library. To do so, add "https://mcudude.github.io/MiniCore/package_MCUdude_MiniCore_index.json" to the preferences list in your IDE, then search for the library in "Boards Manager" and install the package. Configure your board settings to match as follows:

Development Documentation

Challenges

This board had its fair share of challenges. Most notably, this was the first MCU I've worked with directly that required SPI based programming, SPI being a protocol I hadn't used much at all already as it is, much less for programming. In the same realm was the challenge of level shifting the SPI programming signals from a 5V programmer to the 328PB running at 3.3V. Due to the high speed directional nature of SPI finding the right level shifter was a challenge and the first set of boards I ordered actually didn't work due to a level shifter that wasn't capable of handling SPI. Additionally the programming process was entirely new so learning the ropes of programming an MCU via SPI was also a challenge.

What I Learned

I learned quite a bit from this project. I think most notably and as mentioned lots I learned plenty about both level shifters and SPI as these were both brand new for the most part to me. It also helped me develop my board layout skills as this board came out quite compact but with many many components and traces.

Inspiration

This board was most certainly inspired by the Arduino Uno which also uses a 328P Atmel chip as its MCU (though not a PB, to my knowledge). This is a board I've used plenty of times, mainly early in my EE explorations, but that was the back bone of most of my early learning and so was a great inspiration. I was also inspired to simply have a larger chip with more GPIOs available and more storage in case a larger project called for it.