drivers/neopixel: Add common machine.bitstream-based neopixel module.

Signed-off-by: Jim Mussared <jim.mussared@gmail.com>

drivers/neopixel/manifest.py

@@ -0,0 +1,5 @@
+freeze(
+    ".",
+    "neopixel.py",
+    opt=3,
+)

drivers/neopixel/neopixel.py

@@ -0,0 +1,44 @@
+# NeoPixel driver for MicroPython
+# MIT license; Copyright (c) 2016 Damien P. George, 2021 Jim Mussared
+
+from micropython import const
+from machine import bitstream
+
+_BITSTREAM_TYPE_HIGH_LOW = const(0)
+_TIMING_WS2818_800 = (400, 850, 800, 450)
+_TIMING_WS2818_400 = (800, 1700, 1600, 900)
+
+
+class NeoPixel:
+    ORDER = (1, 0, 2, 3)
+
+    def __init__(self, pin, n, bpp=3, timing=1):
+        self.pin = pin
+        self.n = n
+        self.bpp = bpp
+        self.buf = bytearray(n * bpp)
+        self.pin.init(pin.OUT)
+        self.timing = (
+            (_TIMING_WS2818_800 if timing else _TIMING_WS2818_400)
+            if isinstance(timing, int)
+            else timing
+        )
+
+    def __len__(self):
+        return self.n
+
+    def __setitem__(self, index, val):
+        offset = index * self.bpp
+        for i in range(self.bpp):
+            self.buf[offset + self.ORDER[i]] = val[i]
+
+    def __getitem__(self, index):
+        offset = index * self.bpp
+        return tuple(self.buf[offset + self.ORDER[i]] for i in range(self.bpp))
+
+    def fill(self, color):
+        for i in range(self.n):
+            self[i] = color
+
+    def write(self):
+        bitstream(self.pin, _BITSTREAM_TYPE_HIGH_LOW, self.timing, self.buf)