Unit LCD

SKU:U120

Description

Unit LCD is a 1.14-inch color LCD expansion screen unit. It uses the ST7789V2 driver with a resolution of 135 x 240 and supports RGB666 display (262,144 colors). It integrates an ESP32-PICO control core (with built-in firmware, making display development more convenient) and supports control and firmware upgrades via the I2C (addr: 0x3E) communication interface. The back of the screen features a magnetic design, allowing it to easily attach to metal surfaces for fixation. This LCD expansion is suitable for embedding into various instruments or control devices that require simple content display.

Features

• 1.14-inch color LCD display panel
• I2C communication interface
• Viewing angle: Full viewing angle
• Magnetic back design
• Supports I2C firmware upgrade

Includes

• 1 x Unit LCD
• 1 x HY2.0-4P Grove cable (20cm)

Applications

• Information display

Specifications

Schematics

PinMap

Unit LCD

Model Size

Datasheets

• ST7789V2

Softwares

Arduino

• M5GFX Arduino Library

#include <M5UnitLCD.h>

M5UnitLCD display;

M5Canvas canvas(&display);

static constexpr char text[] = "Hello world ! こんにちは世界！ this is long long string sample. 寿限無、寿限無、五劫の擦り切れ、海砂利水魚の、水行末・雲来末・風来末、喰う寝る処に住む処、藪ら柑子の藪柑子、パイポ・パイポ・パイポのシューリンガン、シューリンガンのグーリンダイ、グーリンダイのポンポコピーのポンポコナの、長久命の長助";
static constexpr size_t textlen = sizeof(text) / sizeof(text[0]);
int textpos = 0;
int scrollstep = 2;

void setup(void) 
{
  display.init();
  display.setRotation(2);
  canvas.setColorDepth(1); // mono color
  canvas.setFont(&fonts::lgfxJapanMinchoP_32);
  canvas.setTextWrap(false);
  canvas.setTextSize(2);
  canvas.createSprite(display.width() + 64, 72);
}

void loop(void)
{
  int32_t cursor_x = canvas.getCursorX()-scrollstep;
  if (cursor_x <= 0)
  {
    textpos = 0;
    cursor_x = display.width();
  }

  canvas.setCursor(cursor_x, 0);
  canvas.scroll(-scrollstep, 0);
  while (textpos < textlen && cursor_x <= display.width())
  {
    canvas.print(text[textpos++]);
    cursor_x = canvas.getCursorX();
  }
  display.waitDisplay();
  canvas.pushSprite(&display, 0, (display.height()-canvas.height()) >> 1);
}

Internal Firmware

• Unit LCD Internal Firmware

Protocol

About Unit LCD

• Unit LCD is an I2C unit with ESP32 and ST7789V2.
• It has an IPS panel with a resolution of 135 x 240.
• The number of displayable colors is 262,144 colors in RGB666, which is the specification of ST7789V2.
• ESP32 is responsible for I2C communication and draws the frame buffer in memory based on the received content.
• The content of the frame buffer in ESP32 memory is reflected in ST7789V2 through DMA transfer via SPI communication.
• It is represented by 16,777,216 colors in RGB888 on the frame buffer.

About I2C Communication

• You can use I2C communication to send commands and receive data to/from the Unit LCD.
• The maximum communication speed for I2C communication is 400kHz.
• The initial value of the 7-bit I2C address is 0x3E. It can be changed using the CHANGE_ADDR command.
• The number of bytes required to send depends on the command. Some commands complete within 1 byte, while others require 7 bytes. There are also commands of indefinite length that do not end until communication stops.
• If an I2C communication STOP or RESTART occurs during command transmission, the interrupted command will not be processed. It must be transmitted uninterrupted in a single transmission sequence until the end.
• After sending a fixed-length command, you can send another command continuously.
• After sending an indefinite-length command, you must stop I2C communication to indicate the end of the command.
• If a NOP command or an undefined command is sent, the communication content will be ignored until I2C communication stops.
• Since the I2C communication unit and the drawing processing unit operate in parallel, I2C communication can be performed even during drawing processing.
• The I2C communication content is stored in the command buffer in ESP32 memory, and the drawing processing unit processes it sequentially.
• You should use the READ_BUFCOUNT command to check the remaining amount of the buffer, as sending a large amount of heavy processing, such as extensive filling or range copying, may overflow the buffer.

About Drawing

• You can draw a rectangle by using FILLRECT to fill any area with a single color.
• If you want to draw only one pixel, you can use DRAWPIXEL instead of FILLRECT.
• If you use a command that omits the foreground color, the last used color will be used.
• You can specify the drawing range using CASET and RASET and send image data using the WRITE_RAW command.
• You can use WRITE_RLE instead of WRITE_RAW to send run-length compressed image data.

Command List

※ Undefined commands are treated as no-operation instructions.

Command list (readable commands)

Communication example

The command 6Ah is a total of 7Byte command sequence.
If an I2C communication STOP or RESTART occurs during transmission, the command will not be processed. It is necessary to transmit without interruption until the end in a single transmission sequence.

Any of the rectangle fill commands 68h to 6Ch can be used for rectangle fill. Indexes 1 through 4 are the same, but indexes 5 and onward have different methods for specifying colors.

The "remembered color" of command 68h means that the last specified color will be reused. In other words, if you want to do several rectangular fills of the same color in succession, you can specify the color only for the first rectangular fill and then omit the color specification by using the 68h command.

Command 6Ch, ARGB8888, allows you to specify an alpha channel (transparency), which allows you to combine the already drawn content with the drawing color.

• The RLE specification is based on the RLE for BMP files.
• Unlike RLE for BMP files, it can be used for RGB565 and RGB888.
• It first sends a consecutive number of pixels of the same color (0-255), followed by the color data.
• If 0 is sent to a consecutive number, it will be in direct mode without using RLE.
• In direct mode, the number of pixels (1-255) is sent first, followed by the color data for the number of pixels.

The above example will be handled as follows.

• index1-3 : Draw 7 pixels of red in RLE mode.
• index4-5 : Switch to direct mode and instruct it to draw 3 pixels.
• index6-11: Sends the color for 3 pixels in direct mode and draws green, blue, and red.
• Since the direct mode for 3 pixels is completed by index11, we will return to the RLE mode from index12.
• index12-14 : Draws 4 pixels of blue in RLE mode.

Firmware upgrade

Method 1. Use ESP32-Downloader to download firmware for update

Method 2. Update via I2C communication

Model Size

UIFlow

UIFlow1.0 Unit lcd Docs

UIFlow1.0 Unit lcd Docs

How to use Unit lcd and related API instructions in the UIFlow1.0

Video

• UIFlow2.0 LCD Unit