# SPDX-FileCopyrightText: 2021 Scott Shawcroft, written for Adafruit Industries
#
# SPDX-License-Identifier: MIT

import time
import rp2pio
import board
import microcontroller
import adafruit_pioasm

pixel_count = 10

# NeoPixels are 800khz bit streams. Zeroes are 1/3 duty cycle (~416ns) and ones
# are 2/3 duty cycle (~833ns).
program = """
.program ws2812
.side_set 1
.wrap_target
bitloop:
  out x 1        side 0 [1]; Side-set still takes place when instruction stalls
  jmp !x do_zero side 1 [1]; Branch on the bit we shifted out. Positive pulse
do_one:
  jmp  bitloop   side 1 [1]; Continue driving high, for a long pulse
do_zero:
  nop            side 0 [1]; Or drive low, for a short pulse
.wrap
"""

assembled = adafruit_pioasm.assemble(program)

# If the board has a designated neopixel, then use it. Otherwise use
# GPIO16 as an arbitrary choice.
if hasattr(board, "NEOPIXEL"):
    NEOPIXEL = board.NEOPIXEL
else:
    NEOPIXEL = microcontroller.pin.GPIO16

sm = rp2pio.StateMachine(
    assembled,
    frequency=800000 * 6,  # 800khz * 6 clocks per bit
    first_sideset_pin=NEOPIXEL,
    auto_pull=True,
    out_shift_right=False,
    pull_threshold=8,
)
print("real frequency", sm.frequency)

pixels = bytearray(pixel_count * 3)
for i in range(30):
    for j in range(pixel_count):
      pixels[j * 3 + 0] = (15 * (i + j)) & 0xff
      pixels[j * 3 + 1] = (22 * (i + j)) & 0xff
      pixels[j * 3 + 2] = (33 * (i + j)) & 0xff
    sm.write(pixels)
    time.sleep(0.1)
print("writes done")