The update program can be found in the examples/FirmwareUpdater/ of this repository.
The M5GFX library is required to run the update program.
The update program can be run on the following products.
- M5Stack BASIC / GRAY / GO / FIRE
- M5Stack Core2 / Tough
- M5Stack CoreInk
- M5Stick C / CPlus
- M5Paper
- M5ATOM
Write the update program to one of the above using the ArduinoIDE and connect the Unit.
The update will start automatically.
It is successful when the progress bar reaches the end.
If a communication error occurs during the update, it will be interrupted.
After a certain period of time, the update will start again.
After it is successful, please remove the Unit.
- 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 colors that can be displayed is 262,144 colors of RGB666, which is the specification of ST7789V2.
- The ESP32 is in charge of I2C communication and draws in the frame buffer in memory based on the received contents.
- The contents of the frame buffer in the memory of the ESP32 are reflected in ST7789V2 by DMA transfer of SPI communication.
- It is represented by RGB888 16,777,216 colors on the framebuffer.
- You can send commands and receive data to the Unit LCD using I2C communication.
- The maximum communication speed of I2C communication is 400kHz.
- The initial value of the 7-bit address of I2C is 0x3E. It can be changed with the CHANGE_ADDR command.
- The required number of bytes to send depends on the command.
Some commands complete in 1 Byte, while others require 7 Byte.
There are also indefinite length commands that do not end until communication is stopped. - If I2C communication STOP or RESTART occurs during command transmission, the interrupted command will not be processed.
It must be transmitted uninterrupted to the end in a single transmission sequence. - After sending a fixed-length command, you can send another command in succession.
- After sending an indefinite-length command, I2C communication must be stopped to indicate the end of the command.
- If you send a NOP command or an undefined command, the communication content is 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 the drawing processing.
- The I2C communication contents are stored in the command buffer on the ESP32 memory, and the drawing processing unit processes this 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 fill or range copy, can overwhelm the command buffer.
- You can draw a rectangle by filling any area with a single color with FILLRECT.
- 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 is used.
- You can specify the drawing range with CASET and RASET and send the image data with the WRITE_RAW command.
- You can use WRITE_RLE instead of WRITE_RAW to send run-length compressed image data.
※ Undefined commands are treated as NOP.
| hex | len | command | description | send params |
|---|---|---|---|---|
| 0x00 | 1-∞ | NOP | Do nothing until communication stops | [0] 0x00 [1-∞] Ignored value |
| 0x20 | 1 | INVOFF | Disable color inversion | [0] 0x20 |
| 0x21 | 1 | INVON | Enable color inversion | [0] 0x21 |
| 0x22 | 2 | BRIGHTNESS | Backlight brightness setting 0:Off - 255:Full lights |
[0] 0x22 [1] Brightness(0-255) |
| 0x23 | 7 | COPYRECT | Rectangle range copy | [0] 0x23 [1] Copy source X_Left [2] Copy source Y_Top [3] Copy source X_Right [4] Copy source Y_Bottom [5] Copy destination X_Left [6] Copy destination Y_Top |
| 0x2A | 3 | CASET | X-direction range selection | [0] 0x2A [1] X_Left [2] X_Right |
| 0x2B | 3 | RASET | Y-direction range selection | [0] 0x2B [1] Y_Top [2] Y_Bottom |
| 0x36 | 2 | ROTATE | Set drawing orientation 0:Normal / 1:90° / 2:180° / 3:270° 4-7:flips 0-3 upside down |
[0] 0x36 [1] Setting value (0-7) |
| 0x38 | 2 | SET_POWER | Operating speed setting (power consumption setting) 0:Low speed / 1:Normal / 2:High speed |
[0] 0x38 [1] Setting value (0-2) |
| 0x39 | 2 | SET_SLEEP | LCD panel sleep setting 0:wake up / 1:sleep |
[0] 0x39 [1] Setting value (0-1) |
| 0x3A | 2 | SET_BYTESWAP | Byte swap setting for color data 0:disable(default) / 1:enable |
[0] 0x3A [1] Setting value (0-1) |
| 0x41 | 2-∞ | WRITE_RAW_8 | draw image RGB332 | [0] 0x41 [1] RGB332 until [1] communication STOP. |
| 0x42 | 3-∞ | WRITE_RAW_16 | draw image RGB565 | [0] 0x42 [1-2] RGB565 until [1-2] communication STOP. |
| 0x43 | 4-∞ | WRITE_RAW_24 | draw image RGB888 | [0] 0x43 [1-3] RGB888 until [1-3] communication STOP. |
| 0x44 | 5-∞ | WRITE_RAW_32 | draw image ARGB8888 | [0] 0x44 [1-4] ARGB8888 until [1-4] communication STOP. |
| 0x45 | 2-∞ | WRITE_RAW_A | draw image A8 only alpha channel. Use the last used drawing color. |
[0] 0x45 [1] A8 until [1] communication STOP. |
| 0x49 | 3-∞ | WRITE_RLE_8 | draw RLE image RGB332 | [0] 0x49 [1-∞] RLE Data |
| 0x4A | 4-∞ | WRITE_RLE_16 | draw RLE image RGB565 | [0] 0x4A [1-∞] RLE Data |
| 0x4B | 5-∞ | WRITE_RLE_24 | draw RLE image RGB888 | [0] 0x4B [1-∞] RLE Data |
| 0x4C | 6-∞ | WRITE_RLE_32 | draw RLE image ARGB8888 | [0] 0x4C [1-∞] RLE Data |
| 0x4D | 3-∞ | WRITE_RLE_A | draw RLE image A8 only alpha channel. Use the last used drawing color. |
[0] 0x4D [1-∞] RLE Data |
| 0x50 | 1 | RAM_FILL | Fill the selection with the last used drawing color | [0] 0x50 |
| 0x51 | 2 | SET_COLOR_8 | Specify the drawing color with RGB332 | [0] 0x51 [1] RGB332 |
| 0x52 | 3 | SET_COLOR_16 | Specify the drawing color with RGB565 | [0] 0x52 [1-2] RGB565 |
| 0x53 | 4 | SET_COLOR_24 | Specify the drawing color with RGB888 | [0] 0x53 [1-3] RGB888 |
| 0x54 | 5 | SET_COLOR_32 | Specify the drawing color with ARGB8888 | [0] 0x54 [1-4] ARGB8888 |
| 0x60 | 3 | DRAWPIXEL | Draw single dot Use the drawing color that is stored |
[0] 0x60 [1] X [2] Y |
| 0x61 | 4 | DRAWPIXEL_8 | Draw single dot RGB332 1Byte for drawing color specification |
[0] 0x61 [1] X [2] Y [3] RGB332 |
| 0x62 | 5 | DRAWPIXEL_16 | Draw single dot RGB565 2Byte for drawing color specification |
[0] 0x62 [1] X [2] Y [3-4] RGB565 |
| 0x63 | 6 | DRAWPIXEL_24 | Draw single dot RGB888 3Byte for drawing color specification |
[0] 0x63 [1] X [2] Y [3-5] RGB888 |
| 0x64 | 7 | DRAWPIXEL_32 | Draw single dot ARGB8888 4Byte for drawing color specification Transparent composition with existing drawing contents |
[0] 0x64 [1] X [2] Y [3-6] ARGB8888 |
| 0x68 | 5 | FILLRECT | Fill rectangle Use the drawing color that is stored |
[0] 0x68 [1] X_Left [2] Y_Top [3] X_Right [4] Y_Bottom |
| 0x69 | 6 | FILLRECT_8 | Fill rectangle RGB332 1Byte for drawing color specification |
[0] 0x69 [1] X_Left [2] Y_Top [3] X_Right [4] Y_Bottom [5] RGB332 |
| 0x6A | 7 | FILLRECT_16 | Fill rectangle RGB565 2Byte for drawing color specification |
[0] 0x6A [1] X_Left [2] Y_Top [3] X_Right [4] Y_Bottom [5-6] RGB565 |
| 0x6B | 8 | FILLRECT_24 | Fill rectangle RGB888 3Byte for drawing color specification |
[0] 0x6B [1] X_Left [2] Y_Top [3] X_Right [4] Y_Bottom [5-7] RGB888 |
| 0x6C | 9 | FILLRECT_32 | Fill rectangle ARGB8888 4Byte for drawing color specification Transparent composition with existing drawing contents |
[0] 0x6C [1] X_Left [2] Y_Top [3] X_Right [4] Y_Bottom [5-8] ARGB8888 |
| 0xA0 | 4 | CHANGE_ADDR | I2C address change. prevent unintended execution, [2] specifies the bit inversion value of [1]. |
[0] 0xA0 [1] new I2C address. [2] Bit inversion of [1] [3] 0xA0 |
| hex | len | command | description | return values |
|---|---|---|---|---|
| 0x04 | 1 | READ_ID | ID and firmware version. 4Byte received |
[0] 0x77 [1] 0x89 [2] Major version [3] Minor version |
| 0x09 | 1 | READ_BUFCOUNT | Get remaining command buffer. The higher the value, the more room there is. Can be read out continuously. |
[0] remaining command buffer (0~255) Repeated reception is possible. |
| 0x81 | 1 | READ_RAW_8 | Readout of RGB332 image | [0] RGB332 Repeat [0] until communication STOP. |
| 0x82 | 1 | READ_RAW_16 | Readout of RGB565 image | [0-1] RGB565 Repeat [0-1] until communication STOP. |
| 0x83 | 1 | READ_RAW_24 | Readout of RGB888 image | [0-2] RGB888 Repeat [0-2] until communication STOP. |
Example: Use the Fill Rectangle command 0x6A to fill the rectangle range of X16-31 and Y32-47 with red.
| index | hex | description |
|---|---|---|
| 0 | 0x6A | Fill rectangle RGB565 |
| 1 | 0x10 | X Left |
| 2 | 0x20 | Y Top |
| 3 | 0x1F | X Right |
| 4 | 0x2F | Y Bottom |
| 5 | 0xF8 | Color data RRRRRGGG(red) |
| 6 | 0x00 | Color data GGGBBBBB(red) |
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.
Example: Using the range specification command 0x2A/0x2B and the image transmission command, draw an image in the rectangular range of X 10 to 13 and Y 14 to 17.
| index | hex | description |
|---|---|---|
| 0 | 0x2A | X-direction range selection |
| 1 | 0x0A | X Left(10) |
| 2 | 0x0D | X Right(13) |
| 3 | 0x2B | Y-direction range selection |
| 4 | 0x0E | Y Top(14) |
| 5 | 0x11 | Y Bottom(17) |
| 6 | 0x43 | Draw image RGB888 |
| 7-54 | ?? | Image data(RGB888 ×16) |
- 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.
| index | hex | description |
|---|---|---|
| 0 | 0x4A | Draw RLE image RGB565 |
| 1 | 0x07 | Consecutive number (7pixel) |
| 2-3 | 0xF800 | Color data (red) |
| 4 | 0x00 | Consecutive number (0pixel) switch to direct mode |
| 5 | 0x03 | Consecutive number of direct mode(3pixel) |
| 6-7 | 0x07E0 | Color data (green) |
| 8-9 | 0x001F | Color data (blue) |
| 10-11 | 0xF800 | Color data (red) |
| 12 | 0x04 | Consecutive number (4pixel) |
| 13-14 | 0x001F | Color data (blue) |
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.