Adafruit eInk Feather Friend Board with 32KB SRAM
Adafruit eInk Feather Friend Board with 32KB SRAM is designed to make it easy to add an eInk display. Adafruit has Arduino/CircuitPython drivers for all of Adafruit Feathers, so adding an eInk display makes sense. Just about every small-to-medium size eInk display that has a standard 24-pin connection. This eInk Feather Friend will add all the power supply support circuitry, and level shifting so the user can attach a display (up to tri-color 4.2") and wire it up to a development board.
Using Adafruit CircuitPython or Arduino libraries, the user can create a frame buffer with what pixels they want to have activated and then write that to the display. The eInk Feather Friend comes with a 256Kilobit (32Kilobyte) SRAM chip. That means the user can control up to a 4.2" 300x400 tri-color display (300x400 x 2 colors/8 bits-per-byte = 30KB). This chip shares the SPI port the eInk display uses, so the user only needs one extra pin. The user can use the SRAM to set up whatever the user wants to display, then shuffle data from SRAM to eInk when they are ready. The library from Adafruit does all the work for the user. The user can just interface with it as if it were an Adafruit_GFX compatible display. If it is preferred to use the chip, Adafruit libraries will automatically use the microcontroller/microcomputer internal RAM.
The eInk Feather Friend also has a MicroSD socket so the user can store images, text files, or whatever the user wants to the display. It comes assembled and tested, with some headers. The user will need a soldering iron to attach the header for installing onto the Feather. Stacking headers will let the user put another FeatherWing on top. The eInk Feather Friend does not come with an eInk display or extension cable. It is for use with just about any eInk display that has a 24-pin FPC connector.