10 min

Create, command, and innovate like never before with eINK display and STM32F439ZG

MCU and eINK – A perfect symbiosis

eINK Click with UNI Clicker

Published Nov 07, 2023

Click board™

eINK Click

Development board

UNI Clicker


NECTO Studio



Our adapter solution establishes a perfect symbiosis between the MCU and eINK displays, allowing for smooth, intuitive control and a world of possibilities



Hardware Overview

How does it work?

eINK Click is an adapter Click board™, used to interface a compatible eINK display with the host MCU. The most distinctive feature of the eINK displays is their very low power consumption and the ability to retain the information, even after disconnecting from the power source. The power is consumed only when the display content is changing. The Click board™ comes shipped with the 172x72 eINK display, driven by the integrated SSD1606 controller and it can display 4 shades: black, dark gray, light gray and white. The same type of display is used on the popular Kindle E-readers. The eINK is a reasonably new technology with a promising future. The displayed content does not degrade when exposed to direct sunlight, the display actually behaves like a real paper; it is more readable when there is more light hitting its surface. There is a wide range of applications, where eINK can be implemented: it can be used for very low power consumption applications that require display output, such as mobile phones and wearables, industrial and packaging applications, electronic reading and writing, electronic shelf labels and similar

applications that can utilize this type of display. The working principle of the eINK display is rather simple: there are black and white pigments trapped inside the microcapsules, which are dispersed in a clear fluid between two electrodes. The white pigments are positively charged, while the black pigments are negatively charged. When the electromagnetic field is formed between the electrodes, the pigments get repelled or attracted to the electrodes, depending on the field orientation. This results in bright or dark pigments being positioned towards the bottom or top surface of the microcapsule. When the black pigments are positioned on the top surface of the microcapsule, it is observed as the black pixel, and vice versa. It is also possible to position the pigment charges so that each color occupies one half of the microcapsule top surface and that is how gray shades are produced. The display included with the eINK click is the EA-EPA20-A, a 2 inch,172x72 pixels ePAPER display with the integrated SSD1606 driver/controller, from Electronic Assembly. This display uses the SPI communication protocol for the communication

with the host MCU. This display features inherently wide viewing angle and high contrast, as well as good readability in daylight conditions. The click board™ itself carries the supporting electronics, used to provide all the necessary voltages for the proper operation of the EPA20-A display. The SSD1606 pins are routed through the flat cable of the display and connected via the 24pin, 0.5mm ZIF connector on the click board. From there, the command and data lines are routed to the appropriate pins on the mikroBUS™ of the eINK click. The eINK click also contains the LM75 thermal sensor, which uses I2C protocol to communicate with the SSD1606 driver IC. This is required for thermal compensation of the display, so it can be operated in a wide temperature range, from 0°C to +50°C. The total power consumption of this device is very low. The power is only required when rearranging of the microcell pigments is required, while no power is required to sustain the content of the display. The display retains the content, even when the power is disconnected. The click board and the display are powered via the 3.3V rail of the mikroBUS™.

eINK Click - without display hardware overview image

Features overview

Development board

UNI Clicker is a compact development board designed as a complete solution that brings the flexibility of add-on Click boards™ to your favorite microcontroller, making it a perfect starter kit for implementing your ideas. It supports a wide range of microcontrollers, such as different ARM, PIC32, dsPIC, PIC, and AVR from various vendors like Microchip, ST, NXP, and TI (regardless of their number of pins), four mikroBUS™ sockets for Click board™ connectivity, a USB connector, LED indicators, buttons, a debugger/programmer connector, and two 26-pin headers for interfacing with external electronics. Thanks to innovative manufacturing technology, it allows you to build

gadgets with unique functionalities and features quickly. Each part of the UNI Clicker development kit contains the components necessary for the most efficient operation of the same board. In addition to the possibility of choosing the UNI Clicker programming method, using a third-party programmer or CODEGRIP/mikroProg connected to onboard JTAG/SWD header, the UNI Clicker board also includes a clean and regulated power supply module for the development kit. It provides two ways of board-powering; through the USB Type-C (USB-C) connector, where onboard voltage regulators provide the appropriate voltage levels to each component on the board, or using a Li-Po/Li

Ion battery via an onboard battery connector. All communication methods that mikroBUS™ itself supports are on this board (plus USB HOST/DEVICE), including the well-established mikroBUS™ socket, a standardized socket for the MCU card (SiBRAIN standard), and several user-configurable buttons and LED indicators. UNI Clicker is an integral part of the Mikroe ecosystem, allowing you to create a new application in minutes. Natively supported by Mikroe software tools, it covers many aspects of prototyping thanks to a considerable number of different Click boards™ (over a thousand boards), the number of which is growing every day.

UNI clicker double image

Microcontroller Overview

MCU Card / MCU



8th Generation


ARM Cortex-M4

MCU Memory (KB)


Silicon Vendor


Pin count


RAM (Bytes)


You complete me!


The E-Paper 2.13" display is based on Active Matrix Electrophoretic Display (AMEPD) technology and has an integrated pixel driver, which uses the SPI interface to communicate with the host MCU. The display has a 24-pin flat-printed cable that connects to the host controller. A perfect solution for easy connection is offered in the form of a Click board™. The E-Paper 2.13" display has a resolution of 122(V) X 250(H) pixels and an active display area of 23.71 X 48.55. The size of its square-shaped pixels is 0.194mm x 0.194mm. Thanks to the AMEPD technology, the screen displays clear and crisp graphics and has an ultra-wide viewing range. Another key feature of the E-Ink technology is the extremely low power consumption, even when the display actively refreshes its content.

eINK Click accessories image

Used MCU Pins

mikroBUS™ mapper

SPI Chip Select
SPI Clock
Power Supply
Busy indicator

Take a closer look


eINK Click - without display Schematic schematic

Step by step

Project assembly

UNI Clicker front image hardware assembly

Start by selecting your development board and Click board™. Begin with the UNI Clicker as your development board.

UNI Clicker front image hardware assembly
GNSS2 Click front image hardware assembly
SiBRAIN for STM32F745VG front image hardware assembly
Prog-cut hardware assembly
GNSS2 Click complete accessories setup image hardware assembly
UNI Clicker Access MB 1 - upright/background hardware assembly
Necto image step 2 hardware assembly
Necto image step 3 hardware assembly
Necto image step 4 hardware assembly
Necto image step 5 hardware assembly
Necto image step 6 hardware assembly
Necto image step 7 hardware assembly
Necto No Display image step 8 hardware assembly
Necto image step 9 hardware assembly
Necto image step 10 hardware assembly
Debug Image Necto Step hardware assembly

Track your results in real time

Application Output

After loading the code example, pressing the "DEBUG" button builds and programs it on the selected setup.

Application Output Step 1

After programming is completed, a header with buttons for various actions available in the IDE appears. By clicking the green "PLAY "button, we start reading the results achieved with Click board™.

Application Output Step 3

Upon completion of programming, the Application Output tab is automatically opened, where the achieved result can be read. In case of an inability to perform the Debug function, check if a proper connection between the MCU used by the setup and the CODEGRIP programmer has been established. A detailed explanation of the CODEGRIP-board connection can be found in the CODEGRIP User Manual. Please find it in the RESOURCES section.

Application Output Step 4

Software Support

Library Description

This library contains API for eINK Click driver.

Key functions:

  • eink200_set_lut - Set LUT table

  • eink200_display_image - Displays image

  • eink200_set_font - Set text font

Open Source

Code example

This example can be found in NECTO Studio. Feel free to download the code, or you can copy the code below.

 * \file 
 * \brief Eink200Inch Click example
 * # Description
 * This application demonstrates the use of eINK click board.
 * The demo application is composed of two sections :
 * ## Application Init 
 * Initializes the driver and configures the click board for 2.00 inch eINK display.
 * After that, if the TEXT mode is supported, shows a desired text messages on the display.
 * ## Application Task  
 * Draws two demo images to the display with a one-second delay between each drawing.
 * @note 
 * Due to insuficient RAM memory, only the IMAGE mode is supported with 8-bit PIC microcontrollers.
 * Here is the procedure for creating an Image or Font arrays:
 * - Create Image:
 *    Save the image in resolution of 172x72 px with the extension (jpg) ...
 *    Upload the image to Image2Lcd program
 *    Set parameters to:
 *           1. Output file type : C array
 *           2. Scan Mode : Vertical scan
 *           3. Bits Pixel : 4 Color
 *           4. Max Width and Height : 172x72
 *           5. Select only MSB first checkmark
 *           6. Check Reverse color and adjust Normal type
 *    The image to be generated should contain exact 3096 bytes ...
 *    Insert the image into the file eINK_200_display_image.h
 * - Create Font:
 *    Create a new VisualTFT project
 *    Add label and adjust text font
 *    Generate source code
 *    Copy the font array from resource.c file and paste it to eINK_200_display_font.h file
 * *** Changing the LUT table can lead to loss of display performance ....
 * \author MikroE Team
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "eink_200inch.h"
#include "eINK_200_display_image.h"
#include "eINK_200_display_font.h"

// ------------------------------------------------------------------ VARIABLES

static eink_200inch_t eink_200inch;

const uint8_t EINK200_LUT_TABLE[ 90 ] =
    0x82, 0x00, 0x00, 0x00, 0xAA, 0x00, 0x00, 0x00,
    0xAA, 0xAA, 0x00, 0x00, 0xAA, 0xAA, 0xAA, 0x00,
    0x55, 0xAA, 0xAA, 0x00, 0x55, 0x55, 0x55, 0x55,
    0xAA, 0xAA, 0xAA, 0xAA, 0x55, 0x55, 0x55, 0x55,
    0xAA, 0xAA, 0xAA, 0xAA, 0x15, 0x15, 0x15, 0x15,
    0x05, 0x05, 0x05, 0x05, 0x01, 0x01, 0x01, 0x01,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x41, 0x45, 0xF1, 0xFF, 0x5F, 0x55, 0x01, 0x00,
    0x00, 0x00


char demo_text[ 5 ] = { 'e', 'I', 'N', 'K' , 0 };
char demo_text1[ 8 ] = { 'D', 'i', 's', 'p', 'l', 'a', 'y', 0 };
char demo_text2[ 10 ] = { '2', '.', '0', '0', 'i', 'n', 'c', 'h', 0 };

// ------------------------------------------------------ APPLICATION FUNCTIONS

void application_init ( void )
    eink_200inch_cfg_t cfg;   
    eink_200inch_font_t cfg_font;
    eink_200_text_set_t text_set;

    //  Click initialization.
    eink_200inch_cfg_setup( &cfg );
    eink_200inch_init( &eink_200inch, &cfg );

    eink200_start_config( &eink_200inch );
    eink200_set_lut( &eink_200inch, EINK200_LUT_TABLE, 90 );
    Delay_ms( 1000 );

    cfg_font.p_font = &guiFont_Tahoma_10_Regular[ 0 ];
    cfg_font.color = EINK200_SCREEN_COLOR_WHITE;
    cfg_font.orientation = EINK200_FO_HORIZONTAL;  
    eink200_set_font( &eink_200inch, &cfg_font );
    text_set.n_char = 4;
    text_set.text_x = 10;
    text_set.text_y = 50;
    eink200_text( &eink_200inch, &demo_text[ 0 ], &text_set );
    text_set.n_char = 7;
    text_set.text_x = 10;
    text_set.text_y = 90;
    eink200_text( &eink_200inch, &demo_text1[ 0 ], &text_set );
    text_set.n_char = 8;
    text_set.text_x = 10;
    text_set.text_y = 130;
    eink200_text( &eink_200inch, &demo_text2[ 0 ], &text_set ); 
    Delay_ms( 5000 );

void application_task ( void )
    eink200_display_image ( &eink_200inch, demo_image_black );
    Delay_1sec( );
    eink200_display_image ( &eink_200inch, demo_image_white );
    Delay_1sec( );

void main ( void )
    application_init( );
    for ( ; ; )
        application_task( );

// ------------------------------------------------------------------------ END

Additional Support