MicroPython P9813

A MicroPython library for P9813 RGB LED drivers.

For example, the Seeed Studio Grove - Chainable RGB LED.

Installation

Using mip via mpremote:

$ mpremote mip install github:mcauser/micropython-p9813
$ mpremote mip install github:mcauser/micropython-p9813/examples

Using mip directly on a WiFi capable board:

>>>importmip>>>mip.install("github:mcauser/micropython-p9813")
>>>mip.install("github:mcauser/micropython-p9813/examples")

Manual installation:

Copy src/p9813.py to the root directory of your device.

SPI Version

You can use either HSPI or SPI. This version is significantly faster than the bit-bang version. MISO is not used. The LED driver is write only.

SPI Example

Basic usage

importp9813num_leds=10auto_write=False# Using Hardware SPIfrommachineimportSPI, Pinspi=SPI(1, 10000000, sck=Pin(18), mosi=Pin(23), miso=Pin(19)) # TinyPICOchain=p9813.P9813_SPI(spi, num_leds, auto_write)
# Or using Software SPI# from machine import SoftSPI, Pin# spi = SoftSPI(baudrate=100000, polarity=1, phase=0, sck=Pin(4), mosi=Pin(5), miso=Pin(6)) # TinyS2# chain = p9813.P9813_SPI(spi, num_leds, auto_write)# Set the first LED to red. (red, green, blue)# In a chain, the first LED is closest to the MCUchain[0] = (255, 0, 0)
# Set the second LED to greenchain[1] = (0, 255, 0)
# Set third LED to blue and forth LED magentachain[2:4] = [(0, 0, 255), (255, 0, 255)]
# Write data to all LEDschain.write()
# What colour is the forth LED?print(chain[3])
# (255, 0, 255)# How many LEDs in the chain again?print(len(chain))
# 10# What are the first two colours?print(chain[0:2])
# [(255, 0, 0), (0, 255, 0)]# What are all the colours?print(chain)
# [(255, 0, 0), (0, 255, 0), (0, 0, 255), (255, 0, 255), (0, 0, 0), (0, 0, 0), (0, 0, 0), (0, 0, 0), (0, 0, 0), (0, 0, 0)]# Turn on auto-write, so you don't have to call write() after each changechain.auto_write=True# Make all LEDs redchain.fill((255,0,0))
# Make all LEDs greenchain[0:10] = [
(0, 255, 0),
(0, 255, 0),
(0, 255, 0),
(0, 255, 0),
(0, 255, 0),
(0, 255, 0),
(0, 255, 0),
(0, 255, 0),
(0, 255, 0),
(0, 255, 0),
]
# Draw a rainbow by modifying the buffer directly# Each 4 bytes = 1 LED (checksum, blue, green, red)chain._buf=bytearray(b"\xc3\x00\x00\xff\xc6\x00K\xb4\xc9\x00\x99f\xcc\x00\xe4\x1b\xcc3\xcc\x00\xe4\x81~\x00\xf0\xcc3\x00\xf0\xe4\x00\x1b\xe1\x99\x00f\xd2K\x00\xb4")
chain.write()
# Turn off all LEDschain.reset()

Bit Bang Version

This version works exactly like as the SPI version, only the serial data is written by sending pulses on two output pins (clock and data).

Bit Bang Example

Basic Usage

importp9813num_leds=10auto_write=FalsefrommachineimportPinpin_clk=Pin(4, Pin.OUT)
pin_data=Pin(5, Pin.OUT)
chain=p9813.P9813_BITBANG(pin_clk, pin_data, num_leds, auto_write)
# Make all LEDs redchain.fill((255, 0, 0))
# Set the second LED to greenchain[1] = (0, 255, 0)
# Set the last 8 LEDs to bluechain[2:] = [(0, 0, 255)] *8# Turn off all LEDschain.reset()

For more detailed examples, see examples.

If you mip installed them above, you can run them like so:

importp9813.examples.basic

Chaining

You can connect multiple LEDs together to form a chain. For each additional LED, an additional 4 bytes need to be sent per refresh. The more LEDs you add, the longer it takes to write.

Parts

• Grove - Chainable RGB LED
• Grove 4P Universal Buckled Cable
• Grove 4P Male Dupont Conversion Cable
• TinyPICO
• TinyS2
• WeMos D1 Mini

Connections

Grove Chainable RGB LED	TinyPICO (ESP32)
CI (clock) (yellow)	4
DI (data) (white)	14
VCC (red)	3V3
GND (black)	GND

Grove Chainable RGB LED	TinyS2 (ESP32s2)
CI (clock) (yellow)	4
DI (data) (white)	5
VCC (red)	3V3
GND (black)	GND

Grove Chainable RGB LED	WeMos D1 Mini (ESP8266)
CI (clock) (yellow)	D2 (GPIO4)
DI (data) (white)	D1 (GPIO5)
VCC (red)	3V3 (or 5V)
GND (black)	GND

If you are using the bit-banged version, you can use any output GPIO pins for clock + data.

If you are using the SPI version, you need to use the SPI pins available to your MCU.

If you are chaining multiple LEDs, clock out -> clock in, data out -> data in, eg.

LED1	LED2
CO	CI (yellow)
DO	DI (white)
VCC	VCC (red)
GND	GND (black)

Links

• micropython.org
• P9813 datasheet
• TinyPICO Getting Started
• WeMos D1 Mini

License

Licensed under the MIT License.

Copyright (c) 2017 Mike Causer