Reading and writing to SPI SDcards (Micropython)

Serial Peripheral Interconnect (SPI) is one of the most ubiquitous interconnects used for “high speed” data transfers with MCUs, and for early-stage system bring up (bios for example). One of the more interesting offshoots is that modern SD cards are secretly just storage devices sitting on an SPI bus. This tutorial will focus on a high-level overview of SPI, the protocol, and why it’s different than things like I2C, and walk through the practical example of getting a sdcard working from MicroPython.