Reverse Engineered Raspberry Pi Compute Module 5

Summary

Reverse Engineered Raspberry Pi Compute Module 5 This is the reverse engineered schematic and layout for a Raspberry Pi Compute Module 5. It's not meant to be fabricated--critical signal integrity parameters aren't correct, it's not 100% faithful to the original, the footprints aren't a perfect match, and the bill of materials is not reverse engineered. You also won't be able to obtain most of the chips since they are custom for this design or only available to large customers, not through a distributor. I'm sure folks will want the schematic of the regular Pi 5, but I don't have plans to reverse engineer that. Schematic PDF Bonus schematic of the RM0 WiFi/Bluetooth module I needed to solve some design issues with a project that uses one of these modules, but the schematic was not available. Fortunately, with a little reverse engineering work, I was able to back out the schematic and solve my design issues. It's useful mainly for educational purposes or advanced hacking. For example, now that the PMIC pinout is known, the I2C register map could be explored. It's a great little part--if you accidentally blow up a CM5, you might be able to remove everything except for the PMIC, program it over I2C, and use it to power another project. I removed all the parts from the board, measured them with an LCR meter (and VNA, in the case of the ferrite beads), and then sanded down the board one layer at a time, imaging each with a flatbed scanner at 9600 DPI. KiCad layout lets you embed images which is great for tracing. Fun Trivia The resistors in the upper right corner that select the memory and eMMC configuration are not zero-ohm devices. Each possible position has a specific resistor value, forming a resistor divider with a 10K resistor, so that the RP1 can measure the voltage with two ADC inputs and determine the configuration. The board has 10 layers. It is what's known as a 2+6+2 configuration since it has four layers of microvias: layer 1-2, 2-3, 8-9, and 9-10. There are...