https://github.com/jennasys/micropython-max7219

MicroPython driver for MAX7219 7-segment modules
https://github.com/jennasys/micropython-max7219

Last synced: about 2 months ago
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MicroPython driver for MAX7219 7-segment modules

• Host: GitHub
• URL: https://github.com/jennasys/micropython-max7219
• Owner: JennaSys
• License: mit
• Created: 2019-05-21T01:51:50.000Z (over 5 years ago)
• Default Branch: master
• Last Pushed: 2023-05-11T12:55:08.000Z (over 1 year ago)
• Last Synced: 2024-04-03T04:02:51.761Z (9 months ago)
• Language: Python
• Size: 13.7 KB
• Stars: 16
• Watchers: 4
• Forks: 1
• Open Issues: 2
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# micropython-max7219

**MicroPython driver for MAX7219 with 7-segment modules**

* Utilizes user specified SPI bus and CS line.

* Supports cascading MAX7219 devices

* Number of digits per MAX7219 device can be specified

_max7219.py_ uses an internal buffer (array) that is a direct representation of the display when flushed.  So buffer[0] is the leftmost digit in the display and buffer[digits] is the rightmost.  Also, digit0 is the leftmost and digit7 is rightmost for each MAX7219 device.  Cascaded devices add additional digits to the right.  

If you have a pre-wired 7-segment display module that has the rightmost digit as digit0, then set the `reverse` parameter to `True` when you initialize the driver so that the digits will display in the correct order.

If less than 8 digits are connected to the MAX7219, set the `scan_digits` parameter when initializing so that the code propery handles text value inputs and cascading.  The digits initialization value represents the total number of digits across all cascaded devices.

_seven_segment_ascii.py_ maps ascii characters to their segment representations.  `get_char()` uses a DP-G-F-E-D-C-B-A bit order and `get_char2()` uses a DP-A-B-C-D-E-F-G bit order (which is what the MAX7219 specifies).

## ESP8266 Examples

```python

import max7219

display = max7219.SevenSegment(digits=16, scan_digits=8, cs=5, spi_bus=2, reverse=True)

display.text("ABCDEF")

display.number(3.14159)

display.message("Hello World")

display.clear()

```

## Connections

| ESP8266  | MAX7219 LED Driver |

|----------|--------------------|

| 5V       | VCC                |

| GND      | GND                |

| D7 MOSI  | DIN                |

| D3 GPIO0 | CS                 |

|  D5 SCK  | CLK                |

*NOTE: A level shifter (i.e. 2N7000) may be required on the data lines going to the MAX7219 to change the 3.3V logic to 5V*

## Credits

This library is based on:

* [rm-hull's max7219.py (pre-2017 version)](https://github.com/rm-hull/max7219) for the Raspberry Pi ([PyPI Project](https://pypi.org/project/max7219/))

* [dmadison's Segmented LED Display - ASCII Library](https://github.com/dmadison/LED-Segment-ASCII)

## License

Licensed under the [MIT License](http://opensource.org/licenses/MIT).