Electronics Design

This week we had to design our own board that had the basics components plus at least an led and button. I decided to use the recitation video as a guideline for how to design my board and what components to include. Then I added the required led and button. After that I had to route all the parts together. This was the most difficult part to do.

Board Schematic and Eagle

Because I had no experience with electronic design before, I had to learn how to use a design software first. I decided to follow the recitation video to learn Eagle. However the board it creates is different. I asked Anthony if using a SAMD21 chip was okay when the reference board uses a SAMD11. Since this board is just more powerful, he said it was okay so I kept using the same board and schematic as the reciation. I then also added a switch to pin 16 and a resistor plus a led to pin 17.

Once I was done adding all I needed to the schematic, I checked the connections with Anthony. Then I moved onto routing.

Routing

1. I started routing by mushing parts together and drawing routing lines to connect parts to where they needed to be connected. I first connected the usb lines to the board. Then I placed the volatge regulator to the left of the usb so that the ground and 3V3 can wrap around the entire board.
2. Then I started moving parts to surround the board. If they were connected to the bottom of the board, I moved them below the board and continued that pattern for the rest of the board.
3. Once I had all the parts where they made the most sense, I starting adding more routes and seeing where I needed to add jumps.
4. I added a jump for the USBDM wire because the board had the USBDM and USBPM wires flipped so there was no way to get around this.
5. Button and led were super simple to route because there was nothing in the way.
6. The header was where things got interested. It was literally surrounded by resistors and a capacitor. I laid the resistors around the header as close to the side they connect to. However, no matter what I did, I had to use three jumps (resistors with value 0).
7. Problem: I needed to get a wire beneath the header to connect to pins inside the header but I could not get it through no matter what I tried. It turned out I had a library that was outdated. I had to change the footprint of the header by moving the pads out a bit manually. Then I use an 8 mil width route to get under the header. This also proved to be very useful for routing underneath the main chip.