MicroPython Max7219 8x8 LED Matrix
A MicroPython library for the MAX7219 8x8 LED matrix driver using the SPI interface. Supporting custom fonts and cascading matrices.
Features
- Cascading matrices together
- Custom font support
- Extends the FrameBuffer class
- Removes the need to specify offset for text method
- Extendable
Examples
Raspberry Pi Pico
| Pico | max7219 |
|---|---|
| 40 (VBUS) | VCC 5V |
| 38 (GND) | GND |
| 5 (GP3) | DIN |
| 7 (GP5) | CS |
| 4 (GP2) | CLK |
from machine import Pin, SPI
from max7219 import Matrix8x8
spi = SPI(0, baudrate=10000000, polarity=1, phase=0, sck=Pin(2), mosi=Pin(3))
ss = Pin(5, Pin.OUT)
display = Matrix8x8(spi, ss, 4)
# change brightness 1-15
display.brightness(5)
# clear display
display.zero()
display.show()
# show text using FrameBuffer's font
display.text("CODE")
display.show()Docs
- For any change to the
FrameBufferto appear, call the.show()method - You may have to add delays when calling methods, these are documented in the datasheet
- Tested on 1.19.1
Display Text
display = Matrix8x8(...)
display.zero()
display.text("HI!")
display.show()Custom Fonts
Custom fonts (glyphs) can be provided, each glyph must be 8x8. Missing characters will use default characters from FrameBuffer.
GLYPHS = {
"X": [
[0, 0, 0, 0, 0, 0, 0, 0],
[0, 1, 0, 0, 0, 0, 1, 0],
[0, 0, 1, 0, 0, 1, 0, 0],
[0, 0, 0, 1, 1, 0, 0, 0],
[0, 0, 0, 1, 1, 0, 0, 0],
[0, 0, 1, 0, 0, 1, 0, 0],
[0, 1, 0, 0, 0, 0, 1, 0],
[0, 0, 0, 0, 0, 0, 0, 0],
],
}
display = Matrix8x8(...)
display.text_from_glyph("X", GLYPHS)Shutdown / Wake
Shutting down and waking up the display is supported. This should allow a device to consume just 150μA when it's not needed. When the display is woken from shutdown the previous display should appear.
# shutdown display
display.shutdown()
# wake from shutdown
display.wake()Test Mode
Test mode will enable all pixels, shutdown mode has no effect when testing mode is enabled.
# enable test mode
display.test()
# disable test mode
display.test(False)Extending
Scrolling Text
Although not built-in you could add scrolling text like shown in the following example:
from utime import sleep_ms
from max7219 import Matrix8x8
class Matrix8x8Ext(Matrix8x8):
def scroll_text(self, s, ms_delay=100):
s_width = len(s) * 8
n_pixels = self.num * 8
while True:
for x in range(n_pixels, -s_width, -1):
self.zero()
self.text(s, x)
self.show()
sleep_ms(ms_delay)
return s_widthAttribution
- Original code by @mcauser
- Data-Sheet
License
Licensed under the MIT License, found in LICENSE.txt.
