Connecting InkyWhat to a CircuitPython board

InkyWhat was designed to connect directly to a Raspberry Pi, but it can be connected to any board with SPI and I2C and 4 additional IO pins.

This repo shows how to control an InkyWhat using ESP32 S2 dev board (the Unexpected Maker TinyS2 in this case). It should work with any CircuitPython board with sufficient IO.

Pinout

You'll need 10 wires to connect the InkyWhat. The driver currently doesn't read data from the display do SPI data in (MISO) is not required. If you adjust the code a bit, you could also skip the I2C interface beacuse you already know what board you have, right?

Inky	Pin	Tiny S2 Pin	Description
3V3	1	3V3
SDA	3	SDA / IO8	I2C Data -- only needed for eeprom
SCL	5	SCL / IO9	I2C Clock -- only needed for eeprom
#4
GND	6	GND
MOSI	19	SPI MO / IO35	SPI data out (mcu to display)
MISO	21	SPI MI / IO36	Optional - SPI data in (display to mcu)
SCK	23	SPI SCK / IO37	SPI Clock
CE1
5V	2		Not needed
CSEL	24	IO7	SPI Enable
DTA/CMD	15	IO6	Low = SPI send command, High = SPI send data
RESET	13	IO5	Display hardware reset, needed to wake from sleep
BUSY	11	I04	Used to read display busy status

Reference:

• InkyWhat pinout
• TinyS2 pinout

There are 2 versions in this repository:

• inky.py - The original driver ported to CircuitPython
• ssd1619a.py - A new CircuitPython driver for the SSD1619A display controller used in the InkyWhat

Inky driver for CircuitPython

This driver is ported from library/inky/inky.py in the Pimoroni Inky library. It works with the original Red, Black and Yellow Inky What. Pimoroni has not specified the driver chip but the instructions line up with the SSD1619A.

These boards feature an eeprom that allows reading out the board type. See inky_eeprom.py for more details. The original eeprom code was dropped in favor of the CircuitPython driver for the same chip.

Changes from original driver

• Small differences in dealing with arrays/lists etc.
• CircuitPython doesn't have the full numpy lib, especially packbits is missing
• CircuitPython has Bitmap from display IO which makes working with image data much easier
• EEPROM code was replaced with the CircuitPython lib for the same chip
• Supports outputting a bitmap to the display, no drawing support
• Data processing happens in Python, which makes display updates reeeally slow

CircuitPython driver for SSD1619A-based ePaper display

• Uses Adafruit's displayio lib for the display, allowing drawing etc.
• Fast bitmap data processing using CircuitPython's Bitmap class
• This driver is limited to original 3-color 400x300 InkyWhat, other versions use different display controllers