229 lines
8.5 KiB
Python
229 lines
8.5 KiB
Python
# DotStar strip driver for MicroPython
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#
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# The MIT License (MIT)
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#
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# Copyright (c) 2016 Damien P. George (original Neopixel object)
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# Copyright (c) 2017 Ladyada
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# Copyright (c) 2017 Scott Shawcroft for Adafruit Industries
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# Copyright (c) 2019 Matt Trentini (porting back to MicroPython)
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#
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# Permission is hereby granted, free of charge, to any person obtaining a copy
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# of this software and associated documentation files (the "Software"), to deal
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# in the Software without restriction, including without limitation the rights
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# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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# copies of the Software, and to permit persons to whom the Software is
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# furnished to do so, subject to the following conditions:
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#
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# The above copyright notice and this permission notice shall be included in
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# all copies or substantial portions of the Software.
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#
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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# THE SOFTWARE.
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START_HEADER_SIZE = 4
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LED_START = 0b11100000 # Three "1" bits, followed by 5 brightness bits
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# Pixel color order constants
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RGB = (0, 1, 2)
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RBG = (0, 2, 1)
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GRB = (1, 0, 2)
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GBR = (1, 2, 0)
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BRG = (2, 0, 1)
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BGR = (2, 1, 0)
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class DotStar:
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"""
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A sequence of dotstars.
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:param SPI spi: The SPI object to write output to.
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:param int n: The number of dotstars in the chain
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:param float brightness: Brightness of the pixels between 0.0 and 1.0
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:param bool auto_write: True if the dotstars should immediately change when
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set. If False, `show` must be called explicitly.
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:param tuple pixel_order: Set the pixel order on the strip - different
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strips implement this differently. If you send red, and it looks blue
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or green on the strip, modify this! It should be one of the values above
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Example for TinyPICO:
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.. code-block:: python
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from dotstar import DotStar
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from machine import Pin, SPI
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spi = SPI(sck=Pin(12), mosi=Pin(13), miso=Pin(18)) # Configure SPI - note: miso is unused
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dotstar = DotStar(spi, 1)
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dotstar[0] = (128, 0, 0) # Red
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"""
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def __init__(self, spi, n, *, brightness=1.0, auto_write=True,
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pixel_order=BGR):
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self._spi = spi
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self._n = n
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# Supply one extra clock cycle for each two pixels in the strip.
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self.end_header_size = n // 16
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if n % 16 != 0:
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self.end_header_size += 1
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self._buf = bytearray(n * 4 + START_HEADER_SIZE + self.end_header_size)
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self.end_header_index = len(self._buf) - self.end_header_size
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self.pixel_order = pixel_order
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# Four empty bytes to start.
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for i in range(START_HEADER_SIZE):
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self._buf[i] = 0x00
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# Mark the beginnings of each pixel.
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for i in range(START_HEADER_SIZE, self.end_header_index, 4):
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self._buf[i] = 0xff
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# 0xff bytes at the end.
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for i in range(self.end_header_index, len(self._buf)):
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self._buf[i] = 0xff
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self._brightness = 1.0
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# Set auto_write to False temporarily so brightness setter does _not_
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# call show() while in __init__.
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self.auto_write = False
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self.brightness = brightness
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self.auto_write = auto_write
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def deinit(self):
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"""Blank out the DotStars and release the resources."""
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self.auto_write = False
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for i in range(START_HEADER_SIZE, self.end_header_index):
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if i % 4 != 0:
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self._buf[i] = 0
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self.show()
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if self._spi:
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self._spi.deinit()
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def __enter__(self):
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return self
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def __exit__(self, exception_type, exception_value, traceback):
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self.deinit()
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def __repr__(self):
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return "[" + ", ".join([str(x) for x in self]) + "]"
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def _set_item(self, index, value):
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"""
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value can be one of three things:
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a (r,g,b) list/tuple
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a (r,g,b, brightness) list/tuple
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a single, longer int that contains RGB values, like 0xFFFFFF
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brightness, if specified should be a float 0-1
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Set a pixel value. You can set per-pixel brightness here, if it's not passed it
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will use the max value for pixel brightness value, which is a good default.
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Important notes about the per-pixel brightness - it's accomplished by
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PWMing the entire output of the LED, and that PWM is at a much
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slower clock than the rest of the LEDs. This can cause problems in
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Persistence of Vision Applications
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"""
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offset = index * 4 + START_HEADER_SIZE
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rgb = value
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if isinstance(value, int):
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rgb = (value >> 16, (value >> 8) & 0xff, value & 0xff)
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if len(rgb) == 4:
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brightness = value[3]
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# Ignore value[3] below.
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else:
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brightness = 1
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# LED startframe is three "1" bits, followed by 5 brightness bits
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# then 8 bits for each of R, G, and B. The order of those 3 are configurable and
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# vary based on hardware
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# same as math.ceil(brightness * 31) & 0b00011111
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# Idea from https://www.codeproject.com/Tips/700780/Fast-floor-ceiling-functions
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brightness_byte = 32 - int(32 - brightness * 31) & 0b00011111
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self._buf[offset] = brightness_byte | LED_START
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self._buf[offset + 1] = rgb[self.pixel_order[0]]
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self._buf[offset + 2] = rgb[self.pixel_order[1]]
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self._buf[offset + 3] = rgb[self.pixel_order[2]]
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def __setitem__(self, index, val):
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if isinstance(index, slice):
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start, stop, step = index.indices(self._n)
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length = stop - start
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if step != 0:
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# same as math.ceil(length / step)
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# Idea from https://fizzbuzzer.com/implement-a-ceil-function/
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length = (length + step - 1) // step
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if len(val) != length:
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raise ValueError("Slice and input sequence size do not match.")
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for val_i, in_i in enumerate(range(start, stop, step)):
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self._set_item(in_i, val[val_i])
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else:
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self._set_item(index, val)
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if self.auto_write:
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self.show()
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def __getitem__(self, index):
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if isinstance(index, slice):
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out = []
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for in_i in range(*index.indices(self._n)):
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out.append(
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tuple(self._buf[in_i * 4 + (3 - i) + START_HEADER_SIZE] for i in range(3)))
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return out
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if index < 0:
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index += len(self)
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if index >= self._n or index < 0:
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raise IndexError
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offset = index * 4
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return tuple(self._buf[offset + (3 - i) + START_HEADER_SIZE]
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for i in range(3))
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def __len__(self):
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return self._n
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@property
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def brightness(self):
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"""Overall brightness of the pixel"""
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return self._brightness
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@brightness.setter
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def brightness(self, brightness):
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self._brightness = min(max(brightness, 0.0), 1.0)
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if self.auto_write:
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self.show()
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def fill(self, color):
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"""Colors all pixels the given ***color***."""
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auto_write = self.auto_write
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self.auto_write = False
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for i in range(self._n):
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self[i] = color
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if auto_write:
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self.show()
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self.auto_write = auto_write
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def show(self):
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"""Shows the new colors on the pixels themselves if they haven't already
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been autowritten.
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The colors may or may not be showing after this function returns because
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it may be done asynchronously."""
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# Create a second output buffer if we need to compute brightness
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buf = self._buf
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if self.brightness < 1.0:
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buf = bytearray(self._buf)
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# Four empty bytes to start.
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for i in range(START_HEADER_SIZE):
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buf[i] = 0x00
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for i in range(START_HEADER_SIZE, self.end_header_index):
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buf[i] = self._buf[i] if i % 4 == 0 else int(self._buf[i] * self._brightness)
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# Four 0xff bytes at the end.
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for i in range(self.end_header_index, len(buf)):
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buf[i] = 0xff
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if self._spi:
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self._spi.write(buf)
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