piopixl8.py

# SPDX-FileCopyrightText: 2016 Damien P. George
# SPDX-FileCopyrightText: 2017 Scott Shawcroft for Adafruit Industries
# SPDX-FileCopyrightText: 2019 Carter Nelson
# SPDX-FileCopyrightText: 2019 Roy Hooper
#
# SPDX-License-Identifier: MIT

"""
`neopixel` - PioPixl8 strip driver
====================================================

* Author(s): Damien P. George, Scott Shawcroft, Carter Nelson, Roy Hooper
"""

# pylint: disable=ungrouped-imports
import sys
import digitalio
import _pixelbuf
import _bit_transpose
import rp2pio
import adafruit_pioasm

__version__ = "0.0.0-auto.0"
__repo__ = "https://github.com/adafruit/Adafruit_CircuitPython_PioPixl8.git"

_program = """
.program piopixl8
.side_set 2
;; out bit 1: '595 "ser"
;; side-set bit 1: '595 "srclk" (shift clock)
;; side-set bit 2: '595 "rclk" (latch clock)
;; 1 iteration = 2 cycles
;; 8 iterations + setup = 17 cycles
;; 1 loop = 51 cycles + 1 delay cycle = 52 cycles
;; 800kHz * 52 = 41.60MHz
;; 125MHz / 3 = 41.67MHz

.wrap_target
    set x, 7            side 2
    pull

bitloop0:
    set pins, 1         side 0
    jmp x--, bitloop0   side 1
    set x, 7            side 2
bitloop1:
    out pins, 1         side 0
    jmp x--, bitloop1   side 1
    set x, 7            side 2
bitloop2:
    set pins, 0         side 0
    jmp x--, bitloop2   side 1
.wrap
"""

_assembled = adafruit_pioasm.assemble(_program)

# Pixel color order constants
RGB = "RGB"
"""Red Green Blue"""
GRB = "GRB"
"""Green Red Blue"""
RGBW = "RGBW"
"""Red Green Blue White"""
GRBW = "GRBW"
"""Green Red Blue White"""


class PioPixl8(_pixelbuf.PixelBuf):
    """
    A sequence of neopixels.

    :param ~microcontroller.Pin data: The shift-register's data pin
    :param ~microcontroller.Pin clock: The shift-register's clock pin.  Must directly follow data
    :param ~microcontroller.Pin strobe: The shift-register's strobe pi.  Must directly follow clock
    :param int n: The number of neopixels in each chain.  Must be a multiple of 8
    :param int bpp: Bytes per pixel. 3 for RGB and 4 for RGBW pixels.
    :param float brightness: Brightness of the pixels between 0.0 and 1.0 where 1.0 is full
      brightness
    :param bool auto_write: True if the neopixels should immediately change when set. If False,
      `show` must be called explicitly.
    :param str pixel_order: Set the pixel color channel order. GRBW is set by default.

    Example for Raspberry Pi Pico:

    .. code-block:: python

        pixels = piopixl8.PioPixl8(board.GP0, board.GP1, board.GP2, 8*30, auto_write=False)
        pixels.fill(0xff0000)
        pixels.show()

    .. py:method:: PioPixl8.show()

        Shows the new colors on the pixels themselves if they haven't already
        been autowritten.

        The colors may or may not be showing after this function returns because
        it may be done asynchronously.

    .. py:method:: PioPixl8.fill(color)

        Colors all pixels the given ***color***.

    .. py:attribute:: brightness

        Overall brightness of the pixel (0 to 1.0)

    """

    def __init__(
        self, data, clock, strobe, n, *, bpp=3, brightness=1.0, auto_write=True, pixel_order=None
    ):
        if n % 8:
            raise ValueError("Length must be a multiple of 8")
        if not pixel_order:
            pixel_order = GRB if bpp == 3 else GRBW
        else:
            if isinstance(pixel_order, tuple):
                order_list = [RGBW[order] for order in pixel_order]
                pixel_order = "".join(order_list)

        super().__init__(
            n, brightness=brightness, byteorder=pixel_order, auto_write=auto_write
        )

        self.transposed = bytearray(bpp*n)

        self.sm = rp2pio.StateMachine(
            _assembled,
            frequency=800_000 * 52,
            init=adafruit_pioasm.assemble("set pindirs 7"),
            first_out_pin=data,
            out_pin_count=1,
            first_set_pin=data,
            set_pin_count=3,
            first_sideset_pin=clock,
            sideset_pin_count=2,
            auto_pull=True,
            out_shift_right=False,
            pull_threshold=8,
        )


    def deinit(self):
        """Blank out the PioPixl8s and release the pin."""
        self.fill(0)
        self.show()
        self.sm.deinit()

    def __enter__(self):
        return self

    def __exit__(self, exception_type, exception_value, traceback):
        self.deinit()

    def __repr__(self):
        return "[" + ", ".join([str(x) for x in self]) + "]"

    @property
    def n(self):
        """
        The number of neopixels in the chain (read-only)
        """
        return len(self)

    def _transmit(self, buffer):
        self.sm.write(_bit_transpose.bit_transpose(buffer, output=self.transposed))