Power Pins

• VIN - this is the power pin, connect to 3-5VDC - it has reverse polarity protection but try to wire it right!
• 3V3 out - this is the 3.3V output from the onboard regulator, you can 'borrow' about 100mA if you need to power some other 3.3V logic devices
• GND - this is the power and signal ground pin
• ENA - this pin is all the way on the right. It is connected to the enable pin on the onboard regulator that powers everything. If you want to really have the lowest possible power draw, pull this pin low! Note that if you do so you will cut power to the eInk display but also the SPI RAM (thus erasing it) and the SD card (which means you'll have to re-initialize it when you re-power

Data Control Pins

• SCK - this is the SPI clock input pin, required for e-Ink, SRAM and SD card
• MISO - this is the SPI Microcontroller In Serial Out pin, its used for the SD card and SRAM. It isn't used for the e-Ink display which is write-only, however you'll likely be using the SRAM to buffer the display so connect this one too!
• MOSI - this is the SPI Microcontroller Out Serial In pin, it is used to send data from the microcontroller to the SD card, SRAM and e-Ink display
• ECS - this is the E-Ink Chip Select, required for controlling the display
• D/C - this is the e-Ink Data/Command pin, required for controlling the display
• SRCS - this is the SRAM Chip Select, required for communicating with the onboard RAM chip.
• SDCS - this is the SD card Chip Select, required for communicating with the onboard SD card holder. You can leave this disconnected if you aren't going to access SD cards
• RST - this is the E-Ink ReSeT pin, you may be able to share this with your microcontroller reset pin but if you can, connect it to a digital pin.
• BUSY - this is the e-Ink busy detect pin, and is optional if you don't want to connect the pin (in which case the code will just wait an approximate number of seconds)

EYESPI Display Connector

This connector, located on the back of the board, allows you to connect the display using an EYESPI cable to an EYESPI breakout with no soldering or jumper wires needed.

micro SD Card Slot

On the back of the board, on the left side, is the micro SD card slot. You can use any micro SD card that supports SPI mode with one CS pin.