Arduino library to drive the Memory In Pixel Displays produced by Japan Display Inc.
The library should also work with the Memory In Pixel Displays produced by Sharp (such as LS027B7DH01 or LS044Q7DH01) because they seem to share the same protocol. The only difference with the JDI Displays is that the latter are 8 bit colors while the Sharp ones are monochrome.
Please note that the library has been tested only with the JDI display model LPM027M128B as well as the models listed in Other supported displays section. If you have a different display model feel free to test the library and send PRs.
Reflective displays are readable under direct sunlight and require less power because in bright environments they don't need a backlight! However if you also want to use them in dark environments you may need a display with a backlight panel (like the model LPM027M128C or LPM013M126C).
There is also a different kind of display lighting produced by Azumo: they apply a special thin and transparent film to the front. Check out all the Azumo displays. Some of them are based on Sharp display, others on JDI display. This is the exact display which I bought and used to test the library.
Based on Tadayuki Okamoto's library.
Both the Sharp and JDI Displays are ultra slim and compact. They have a 10 pins FPC connector which can be difficult to handle. Some of them have an extra 2 pin connector for the back/front light panel. I have designed a Breakout board to make it easy to test the display and turn on/off the light.
If you want to make the same test board please check the Schematic, BOM and Gerber files.
Please note that the Breakout board version 1.0 is specifically designed for the JDI MIP Display model LPM027M128B so the position of the FPC connectors might change according to the display model.
This breakout has the following issues:
- R3 in the schematic is 839 Ohm but it is too big therefore the light is weak. I have replaced it by soldering a smaller resistor (27 Ohm).
- The display is powered from 3.3v which is also used to power the frontlight. However there should be a different 5v source to power the frontlight.
- Capacitors C1 and C2 according to the display datasheet should be 0.1uF. They were out of stock when I ordered the board, I then used 100nF instead which should not be a problem but keep that in mind.
Here is a short Demonstration video of the display in action.
| PIN | Description | Connect to |
|---|---|---|
| SCLK | SPI Serial Clock Signal | Connect to MCU SPI Clock |
| SI/MOSI | SPI Serial Data Input Signal also known as MOSI (Master Out Slave In) | Connect to MCU SPI MOSI |
| SCS | SPI Chip Select Signal | Connect to MCU SPI Chip select pin |
| EXTCOMIN | COM Inversion Signal Input | Not connected |
| DISP | Display ON/OFF Switching Signal | Connect to any digital pin |
| EXTMODE | COM Inversion Mode Select Terminal | Not connected |
| FRONTLIGHT | Frontlight ON/OFF Switching Signal | Connect to any digital pin |
| PIN | Teensy 4.1 | Esp8266 | Esp32 |
|---|---|---|---|
| SCLK | 13 | D5 GPIO14 | 18 |
| SI/MOSI | 11 | D7 GPIO13 | 23 |
| SCS | 10 | D8 GPIO15 | 5 |
| EXTCOMIN | Not connected | Not connected | Not connected |
| DISP | 22 | D2 GPIO4 | 21 |
| EXTMODE | Not connected | Not connected | Not connected |
| FRONTLIGHT | 23 | D1 GPIO5 | 22 |
This library depends on Adafruit_GFX and Arduino SPI libraries. So make sure to install those first.
In order to maximize the number of Frame Per Second, the library allocates 2 buffers to efficiently draw only the lines that change between two screen refresh. Depending on the display size you may not have enough memory on the microcontroller.
For example for a 400x240 pixel display it is necessary to allocate ~107Kb of dynamic memory. If your microcontroller (for example Esp8266) doesn't have such memory you can disable the different lines update (using only one buffer) by commenting the following line in JDI_MIP_Display.h:
#define DIFF_LINE_UPDATE
By commenting that line the display will be fully updated at every refresh. The FPS will drammatically drop but the required memory will be ~62Kb (400x240 pixel display).
The library is available from the Arduino Library Manager: load the Arduino IDE, then use the menu at the top to select Sketch -> Include Library -> Manage Libraries. Type JDI_MIP_Display in the search box.
Click the following badge for a complete installation guide
Configure the pins according to your wiring scheme by opening Display_cfg.h and define the following:
#define PIN_SCS 10 // SPI Chip Select Signal pin
#define PIN_DISP 22 // Display ON/OFF Switching Signal pin
#define PIN_FRONTLIGHT 23 // Frontlight pin. Optional depending on the display model
Also define the width and height in pixel according to your display model:
#define DISPLAY_WIDTH 400 // Display width in pixel
#define DISPLAY_HEIGHT 240 // Display height in pixel
Include the library:
#include <JDI_MIP_Display.h>
Create the instance of the display class:
JDI_MIP_Display jdi_display;
Initialize the display by calling the begin function which initializes the buffers and SPI interface. Then turn the display on. Depending on the display model you can also turn the frontlight on or off.
jdi_display.begin();
delay(50);
jdi_display.displayOn();
jdi_display.frontlightOn(); // Optional depending on the display model
You can now use all the functions defined in the Adafruit_GFX library to draw shapes, text, bitmaps and so on. Please refer to the Adrafruit library documentation.
Keep in mind that all the drawing functions like fillCircle, drawCircle, fillRect, print, drawBitmap and so on... just write in the memory buffer, they don't actually update the display. In order to update the display you need to call the refresh function like so:
jdi_display.refresh();
Please check the Examples
Tested by @testudor
Set both DISPLAY_WIDTH and DISPLAY_HEIGHT to 176 in Display_cfg.h
A breakout board for this display can be found here
Tested by @andelf
Set DISPLAY_WIDTH to 72 and DISPLAY_HEIGHT to 144 in Display_cfg.h
This is a 0.850 inch display with a 8 pins FPC or a BM20B(0.8)-10DS-0.4V 10 pins connector.