Hardware Design with the RP2040: Custom PCB Based on the Raspberry Pi Pico | Digi-Key Electronics

Video Description

The Raspberry Pi RP2040 is a new microcontroller with a dual-core Arm Cortex-M0+ and 264 kB of internal RAM. One of the most interesting features of the RP2040 is that it can be configured to debug another RP2040. In this video, we walk you through the design process of creating your own PCB around the RP2040. The board shown is a stackable “shoe” that can be used to debug a separate Raspberry Pi Pico. Design files can be found here: https://github.com/ShawnHymel/rpi-pico-debugger-shoe. They can be opened in KiCad (tested on v5.1). The Raspberry Pi RP2040 Hardware Design guide is a great place to start to learn about creating a custom PCB for the RP2040: https://datasheets.raspberrypi.org/rp2040/hardware-design-with-rp2040.pdf. Note that the video is not a complete walkthrough of how to design a board. Rather, it is a collection of lessons learned and design decisions that went into creating a custom PCB for the RP2040 along with the various mistakes to get to the end product. The schematic is similar to the bare minimum schematic found in the Hardware Design guide. An LED was added to give status codes. An external flash memory chip is necessary for the RP2040 to run code from a nonvolatile storage location. However, we found that the Winbond W25Q series flash chips were necessary for proper function. Using a non-Winbond part resulted in code not executing. Note that non-Winbond flash memory chips may be used, but you will likely need to modify header files in a custom board definition package for your particular design. The board has a similar shape to the Raspberry Pi Pico so that a Pico could stack on top of it. The PCB fabrication service used (DKRed) requires a minimum of 1 inch on either dimension. As a result, the board outline was made slightly wider than the Pico’s so that it could be fabricated. Soldering the RP2040 (QFN package) proved quite difficult, and the soldering job required rework. The QFN could be reseated or removed altogether using flux and a hot air station. Additionally, solder bridges could be fixed using flux and a small, clean soldering iron tip. In the end, the board was able to run the picoprobe firmware and could provide step-through debugging of a Raspberry Pi Pico. Chapter Timestamps: 0:00 - About the RP2040 Hardware 9:57 - Adding Part Libraries to KiCad 12:10 - Schematic 22:18 - PCB Layout 33:11 - Generate Gerbers 38:05 - Reflow Soldering 43:54 - Inspection and Rework 49:02 - Testing Product Links: Raspberry Pi RP2040 - https://www.digikey.com/en/products/detail/SC0908(7)/2648-SC0908(7)CT-ND/14306013?itemSeq=367989738 Related Videos: Intro to KiCad Part 1 - https://www.youtube.com/watch?v=vaCVh2SAZY4 How to Make a Raspberry Pi CM4 Carrier Board Part 1 - https://www.youtube.com/watch?v=ypcPJC_umPQ Related Project Links: Creating a Raspberry Pi CM4 Carrier Board - https://www.digikey.com/en/maker/projects/creating-a-raspberry-pi-compute-module-4-cm4-carrier-board-in-kicad/7812da347e5e409aa28d59ea2aaea490 Related Articles: How to Route Differential Pairs in KiCad - https://www.digikey.com/en/maker/projects/how-to-route-differential-pairs-in-kicad-for-usb/45b99011f5d34879ae1831dce1f13e93 Hardware Design with the Raspberry Pi RP2040 Part 1: Schematic - https://www.digikey.com/en/maker/projects/hardware-design-with-the-rp2040-part-1-schematic/c4326f0fd813413698d617cf625125ee Hardware Design with the Raspberry Pi RP2040 Part 2: PCB Layout - https://www.digikey.com/en/maker/projects/hardware-design-with-the-rp2040-part-2-pcb-layout/850cdf59974a4de3b749f94aa318c1f5 Hardware Design with the Raspberry Pi RP2040 Part 3: Soldering - https://www.digikey.com/en/maker/projects/hardware-design-with-the-rp2040-part-3-soldering-and-testing/5cc550e86cb24327aeb451f879e18e8d Learn more: Maker.io - https://www.digikey.com/en/maker Digi-Key’s Blog – TheCircuit https://www.digikey.com/en/blog Connect with Digi-Key on Facebook https://www.facebook.com/digikey.electronics/ And follow us on Twitter https://twitter.com/digikey