The D1 mini board: http://wemos.cc
Tool used to convert .bmp to byte arrays: http://javl.github.io/image2cpp/
- WeMos D1 Mini
- Nokia 5110 PCD8544 84x48 monochrome LCD
- 8 jumper wires
- breadboard
Add these to your Arduino IDE using Manage Libraries.
- Adafruit GFX Library
- Adafruit PCD8544 Nokia 5110 LCD library
- There is a pull request that adds ESP8266 support:
- adafruit/Adafruit-PCD8544-Nokia-5110-LCD-library#27
- If this has not been merged yet, you will need to manually copy the changes across
| WeMos D1 Mini | Nokia 5110 PCD8544 LCD | Description |
|---|---|---|
| D2 (GPIO4) | 0 RST | Output from ESP to reset display |
| D1 (GPIO5) | 1 CE | Output from ESP to chip select/enable display |
| D6 (GPIO12) | 2 DC | Output from display data/command to ESP |
| D7 (GPIO13) | 3 Din | Output from ESP SPI MOSI to display data input |
| D5 (GPIO14) | 4 Clk | Output from ESP SPI clock |
| 3V3 | 5 Vcc | 3.3V from ESP to display |
| D0 (GPIO16) | 6 BL | 3.3V to turn backlight on, or PWM |
| G | 7 Gnd | Ground |
These connections are common to all examples.
The backlight (BL) is optional. If you would like full brightness all the time, connect BL to 3V3 and save D0 for something else.
I used this tool to convert bitmap images into byte arrays. http://javl.github.io/image2cpp/
The Adafruit library drawBitmap() expects steam of bytes which are drawn horizontally. The first 0xFF in the array represents the first 8x pixels in the top left corner moving to the right.
Each rows last byte needs to be padded with least significant bits to make it a full byte.
I expected a 5x2 black square image would be exactly 10 bits in the array, however, it appears you need 16 bits with 3 padding bits at the end of each row.
The padding least significant bits in the last byte per row are seemingly ignored.
// 5x2 black rectangle
ABCDE
FGHIJ
// last byte on each row zero padded
ABCDE000
FGHIJ000
// as bits
11111000
11111000
// as bytes
0B11111000, 0B11111000
0xF8, 0xF8
// 9x2 black rectangle
ABCDEFGHI
JKLMNOPQR
// last byte on each row zero padded
ABCDEFGH I0000000
JKLMNOPQ R0000000
// as bits
11111111 10000000
11111111 10000000
// as bytes
0B11111111, 0B10000000, 0B11111111, 0B10000000
0XFF, 0x80, 0XFF, 0x80
To make the image2cpp tool output an Adafruit compatible byte array, you need to upload an image then round up the width to make it divisble by 8. eg. Upload a 84x48 image, then adjust the width to 88x48 then generate the bytes. Upload a 9x2 image and you need to change the size to 16x2 then generate.
The internal buffer in the library stores the bits in 6 rows of 84x columns of 8 bits. Completely different to what drapBitmap() accepts!