Only 11 years late to the game… with ESPs now ubiquitous (at 3.3V, so no level shifter needed), I ended up using SPI mode to get the raw image of an otherwise unaccessible SD card (and evtl ...

Schematic of Dmitri’s SpringSD board for Handspring Visor PDAs. To make the M68k bus traffic look somewhat SPI-like to an SPI slave, ... I think with micro-SD, ...

To display the email count (and retain the Arduino-y-ness of the Galileo) I used an OpenSegment Shield, controlled over SPI. No modifications, just plop it right on top of the Galileo. A lot of the ...