FT232Hボードにneopixelsを接続する

2020/4/4

FT232H neopixels(spi)

FT232H neopixels(spi)

概要

以下のFT232Hボードにneopixelsを接続する。

ＦＴ２３２Ｈ使用ＵＳＢ⇔ＧＰＩＯ＋ＳＰＩ＋Ｉ２Ｃ変換モジュール
Adafruit FT232H Breakout
PCのpython3でCircuitPythonのAPIを使用する

接続

D1(MOSI)をneopixelsのDINに接続する。

demo1

Module Install:

  pip3 install adafruit-circuitpython-neopixels_spi

  

Demo Script:
neopixel_spi_test.py

  # FT232H board
  import math
  from time import sleep
  import board
  import neopixel_spi as neopixel

  NUM_PIXELS = 64
  PIXEL_ORDER = neopixel.GRB
  COLORS = (0xFF0000, 0x00FF00, 0x0000FF)
  DELAY = 0.1

  spi = board.SPI()

  pixels = neopixel.NeoPixel_SPI(spi,
                                 NUM_PIXELS,
                                 pixel_order=PIXEL_ORDER,
                                 auto_write=False)

  def show_pixels(data):
      for n in range(NUM_PIXELS):
          pixels[n] = data[n]
      pixels.show()


  def data_generator(led_count):
        data = [(0, 0, 0) for i in range(led_count)]
        step = 0
        while True:
            red = int((1 + math.sin(step * 0.1324)) * 127)
            green = int((1 + math.sin(step * 0.1654)) * 127)
            blue = int((1 + math.sin(step * 0.1)) * 127)
            data[step % led_count] = (red, green, blue)
            yield data
            step += 1

  for data in data_generator(NUM_PIXELS):
        show_pixels(data)
        sleep(0.01)

  

実行:

  $ export BLINKA_FT232H=1
  $ python3 neopixel_spi_test.py

  

demo2

Module Install:

  git clone https://github.com/JanBednarik/micropython-ws2812.git
  cd micropython-ws2812
  cp ws2812.py ws2812_spi0_cpy.py

  nano ws2812_spi0_cpy.py 
  # 次の「Patched Module」に記載されているパッチを反映する。

  cp ws2812_spi0_cpy.py  ~/ft232h_ws/

  

Patched Module:
ws2812_spi0_cpy.py
「#m」を含む行が修正行になる。

  # -*- coding: utf-8 -*-

  import gc
  #m import pyb
  import board #m
  import busio #m

  class WS2812:
      """
      Driver for WS2812 RGB LEDs. May be used for controlling single LED or chain
      of LEDs.

      Example of use:

          chain = WS2812(spi_bus=1, led_count=4)
          data = [
              (255, 0, 0),    # red
              (0, 255, 0),    # green
              (0, 0, 255),    # blue
              (85, 85, 85),   # white
          ]
          chain.show(data)

      Version: 1.0
      """
      buf_bytes = (0x88, 0x8e, 0xe8, 0xee)

      def __init__(self, spi_bus=1, led_count=1, intensity=1):
          """
          Params:
          * spi_bus = SPI bus ID (1 or 2)
          * led_count = count of LEDs
          * intensity = light intensity (float up to 1)
          """
          self.led_count = led_count
          self.intensity = intensity

          # prepare SPI data buffer (4 bytes for each color)
          self.buf_length = self.led_count * 3 * 4
          self.buf = bytearray(self.buf_length)

          # SPI init
          #m self.spi = pyb.SPI(spi_bus, pyb.SPI.MASTER, baudrate=3200000, polarity=0, phase=1)
          self.spi = busio.SPI(clock=board.SCK, MOSI=board.MOSI) #m
          self.spi.try_lock() #m
          self.spi.configure(baudrate=3200000, polarity=0, phase=0) #m

          # turn LEDs off
          self.show([])

      def show(self, data):
          """
          Show RGB data on LEDs. Expected data = [(R, G, B), ...] where R, G and B
          are intensities of colors in range from 0 to 255. One RGB tuple for each
          LED. Count of tuples may be less than count of connected LEDs.
          """
          self.fill_buf(data)
          self.send_buf()

      def send_buf(self):
          """
          Send buffer over SPI.
          """
          #m self.spi.send(self.buf)
          self.spi.write(self.buf) #m
          #m gc.collect()

      def update_buf(self, data, start=0):
          """
          Fill a part of the buffer with RGB data.

          Order of colors in buffer is changed from RGB to GRB because WS2812 LED
          has GRB order of colors. Each color is represented by 4 bytes in buffer
          (1 byte for each 2 bits).

          Returns the index of the first unfilled LED

          Note: If you find this function ugly, it's because speed optimisations
          beated purity of code.
          """

          buf = self.buf
          buf_bytes = self.buf_bytes
          intensity = self.intensity

          mask = 0x03
          index = start * 12
          for red, green, blue in data:
              red = int(red * intensity)
              green = int(green * intensity)
              blue = int(blue * intensity)

              buf[index] = buf_bytes[green >> 6 & mask]
              buf[index+1] = buf_bytes[green >> 4 & mask]
              buf[index+2] = buf_bytes[green >> 2 & mask]
              buf[index+3] = buf_bytes[green & mask]

              buf[index+4] = buf_bytes[red >> 6 & mask]
              buf[index+5] = buf_bytes[red >> 4 & mask]
              buf[index+6] = buf_bytes[red >> 2 & mask]
              buf[index+7] = buf_bytes[red & mask]

              buf[index+8] = buf_bytes[blue >> 6 & mask]
              buf[index+9] = buf_bytes[blue >> 4 & mask]
              buf[index+10] = buf_bytes[blue >> 2 & mask]
              buf[index+11] = buf_bytes[blue & mask]

              index += 12

          return index // 12

      def fill_buf(self, data):
          """
          Fill buffer with RGB data.

          All LEDs after the data are turned off.
          """
          end = self.update_buf(data)

          # turn off the rest of the LEDs
          buf = self.buf
          off = self.buf_bytes[0]
          for index in range(end * 12, self.buf_length):
              buf[index] = off
              index += 1

  

demo1のAdafruit製モジュールよりも表示が速い。たぶん、gc.collect()をコメントアウトしているせいと思われる。PCのpython3で動作させる前提ではメモリが潤沢にあるので gc.collect()は不要と判断した。
注意：APIはAdafruitのものと異なっている。

Demo Script:
ws2812_spi_test.py

  from time import sleep
  import math
  from ws2812_spi0_cpy import WS2812

  #ring = WS2812(led_count=64, intensity=0.1)
  ring = WS2812(led_count=64, intensity=1)

  def data_generator(led_count):
        data = [(0, 0, 0) for i in range(led_count)]
        step = 0
        while True:
            red = int((1 + math.sin(step * 0.1324)) * 127)
            green = int((1 + math.sin(step * 0.1654)) * 127)
            blue = int((1 + math.sin(step * 0.1)) * 127)
            data[step % led_count] = (red, green, blue)
            yield data
            step += 1

  for data in data_generator(ring.led_count):
        ring.show(data)
        sleep(0.01)

  

実行:

  $ export BLINKA_FT232H=1
  $ python3 ws2812_spi_test.py

  

参照情報

FT232H Blinka PINOUT

CircuitPython Libraries on any Computer with FT232H

ＦＴ２３２Ｈ使用ＵＳＢ⇔ＧＰＩＯ＋ＳＰＩ＋Ｉ２Ｃ変換モジュール
Adafruit FT232H Breakout

CircuitPython on Linux and Raspberry Pi
CircuitPython 5.0.x - I2C

以上