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Replace PIO code with an inbuilt timer, based on https://learn.adafru… #20

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Replace PIO code with an inbuilt timer, based on https://learn.adafru… #20

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8c76ff6
Replace PIO code with an inbuilt timer, based on https://learn.adafru…
Feb 5, 2024
16026e5
Back out changes from https://github.com/blaz-r/pi_pico_neopixel/pull/19
Feb 7, 2024
a145677
Add more comments and credits to the source
Feb 7, 2024
51f1f46
Use a single array as a buffer, including header and trailer
Feb 8, 2024
812de90
Remove references to delay as it's no longer needed
Feb 8, 2024
70a84ba
Merge branch 'main' into pio_timer
blaz-r Mar 31, 2024
d281ce4
Optimize and add WS2821 support
blaz-r Apr 1, 2024
4a895e2
Merge branch 'main' into pio_timer
blaz-r Apr 1, 2024
b02b657
Remove unused imports
blaz-r Apr 1, 2024
a288867
Merge branch 'pio_timer' of https://github.com/mcarlson/pi_pico_neopi…
blaz-r Apr 1, 2024
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133 changes: 87 additions & 46 deletions neopixel.py
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Original file line number Diff line number Diff line change
@@ -1,37 +1,62 @@
import array, time
import array
from machine import Pin
import rp2


# PIO state machine for RGB. Pulls 24 bits (rgb -> 3 * 8bit) automatically
@rp2.asm_pio(sideset_init=rp2.PIO.OUT_LOW, out_shiftdir=rp2.PIO.SHIFT_LEFT, autopull=True, pull_thresh=24)
def ws2812():
T1 = 2
T2 = 5
T3 = 3
# based on https://learn.adafruit.com/intro-to-rp2040-pio-with-circuitpython/advanced-using-pio-to-drive-neopixels-in-the-background by https://learn.adafruit.com/u/jepler
@rp2.asm_pio(sideset_init=rp2.PIO.OUT_LOW, out_init=rp2.PIO.OUT_LOW, out_shiftdir=rp2.PIO.SHIFT_LEFT, autopull=False)
def sk6812():
wrap_target()
pull(block) .side(0) # get fresh NeoPixel bit count value
out(y, 32) .side(0) # get count of NeoPixel bits

label("bitloop")
out(x, 1) .side(0) [T3 - 1]
jmp(not_x, "do_zero") .side(1) [T1 - 1]
jmp("bitloop") .side(1) [T2 - 1]
pull(ifempty) .side(0) # drive low
out(x, 1) .side(0) [5]
jmp(not_x, "do_zero") .side(1) [3] # drive high and branch depending on bit val
jmp(y_dec, "bitloop") .side(1) [4] # drive high for a one (long pulse)
jmp("end_sequence") .side(0) # sequence is over

label("do_zero")
nop() .side(0) [T2 - 1]
jmp(y_dec, "bitloop") .side(0) [4] # drive low for a zero (short pulse)

label("end_sequence")
pull(block) .side(0) # get fresh delay value
out(y, 32) .side(0) # get delay count

label("wait_reset")
jmp(y_dec, "wait_reset") .side(0) # wait until delay elapses
wrap()


# PIO state machine for RGBW. Pulls 32 bits (rgbw -> 4 * 8bit) automatically
@rp2.asm_pio(sideset_init=rp2.PIO.OUT_LOW, out_shiftdir=rp2.PIO.SHIFT_LEFT, autopull=True, pull_thresh=32)
def sk6812():
T1 = 2
T2 = 5
T3 = 3
# based on https://learn.adafruit.com/intro-to-rp2040-pio-with-circuitpython/advanced-using-pio-to-drive-neopixels-in-the-background by https://learn.adafruit.com/u/jepler
@rp2.asm_pio(sideset_init=rp2.PIO.OUT_LOW, out_init=rp2.PIO.OUT_LOW, out_shiftdir=rp2.PIO.SHIFT_LEFT, autopull=False)
def ws2812():
wrap_target()
pull(block) .side(0) # get fresh NeoPixel bit count value
out(y, 32) .side(0) # get count of NeoPixel bits

label("bitloop")
out(x, 1) .side(0) [T3 - 1]
jmp(not_x, "do_zero") .side(1) [T1 - 1]
jmp("bitloop") .side(1) [T2 - 1]
jmp(not_osre, "bit_out") .side(0) # if OSR still contains data, skip this section
pull(ifempty) .side(0) # pull new 32bits of RGB data
out(x, 8) .side(0) # skip first 8 as RGB is 24bits

label("bit_out")
pull(ifempty) .side(0) # drive low
out(x, 1) .side(0) [5]
jmp(not_x, "do_zero") .side(1) [3] # drive high and branch depending on bit val
jmp(y_dec, "bitloop") .side(1) [4] # drive high for a one (long pulse)
jmp("end_sequence") .side(0) # sequence is over

label("do_zero")
nop() .side(0) [T2 - 1]
jmp(y_dec, "bitloop") .side(0) [4] # drive low for a zero (short pulse)

label("end_sequence")
pull(block) .side(0) # get fresh delay value
out(y, 32) .side(0) # get delay count

label("wait_reset")
jmp(y_dec, "wait_reset") .side(0) # wait until delay elapses
wrap()


Expand All @@ -46,10 +71,6 @@ def __getitem__(self, slc):
slice_maker = slice_maker_class()


# Delay here is the reset time. You need a pause to reset the LED strip back to the initial LED
# however, if you have quite a bit of processing to do before the next time you update the strip
# you could put in delay=0 (or a lower delay)
#
# Class supports different order of individual colors (GRB, RGB, WRGB, GWRB ...). In order to achieve
# this, we need to flip the indexes: in 'RGBW', 'R' is on index 0, but we need to shift it left by 3 * 8bits,
# so in it's inverse, 'WBGR', it has exactly right index. Since micropython doesn't have [::-1] and recursive rev()
Expand All @@ -64,16 +85,17 @@ class Neopixel:
# to describe the data members...
# __slots__ = [
# 'num_leds', # number of LEDs
# 'pixels', # array.array('I') of raw data for LEDs
# 'pixels', # array.array('I') of raw data for LEDs (with header and trailer)
# 'mode', # mode 'RGB' etc
# 'W_in_mode', # bool: is 'W' in mode
# 'sm', # state machine
# 'shift', # shift amount for each component, in a tuple for (R,B,G,W)
# 'delay', # delay amount
# 'brightnessvalue', # brightness scale factor 1..255
# 'header', # header - num of data bits in the data stream
# 'trailer', # trailer - delay at the end
# ]

def __init__(self, num_leds, state_machine, pin, mode="RGB", delay=0.0003):
def __init__(self, num_leds, state_machine, pin, mode="RGB"):
"""
Constructor for library class

Expand All @@ -82,26 +104,38 @@ def __init__(self, num_leds, state_machine, pin, mode="RGB", delay=0.0003):
:param pin: pin on which data line to led-strip is connected
:param mode: [default: "RGB"] mode and order of bits representing the color value.
This can be any order of RGB or RGBW (neopixels are usually GRB)
:param delay: [default: 0.0001] delay used for latching of leds when sending data
"""
self.pixels = array.array("I", [0] * num_leds)
self.mode = mode
self.W_in_mode = 'W' in mode
bpp = 3
if self.W_in_mode:
# RGBW uses different PIO state machine configuration
self.sm = rp2.StateMachine(state_machine, sk6812, freq=8000000, sideset_base=Pin(pin))
self.sm = rp2.StateMachine(state_machine, sk6812, freq=12_800_000, sideset_base=Pin(pin))
# tuple of values required to shift bit into position (check class desc.)
self.shift = ((mode.index('R') ^ 3) * 8, (mode.index('G') ^ 3) * 8,
(mode.index('B') ^ 3) * 8, (mode.index('W') ^ 3) * 8)
bpp = 4
else:
self.sm = rp2.StateMachine(state_machine, ws2812, freq=8000000, sideset_base=Pin(pin))
self.sm = rp2.StateMachine(state_machine, ws2812, freq=12_800_000, sideset_base=Pin(pin))
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self.shift = (((mode.index('R') ^ 3) - 1) * 8, ((mode.index('G') ^ 3) - 1) * 8,
((mode.index('B') ^ 3) - 1) * 8, 0)
self.sm.active(1)
self.num_leds = num_leds
self.delay = delay
self.brightnessvalue = 255

# from https://learn.adafruit.com/intro-to-rp2040-pio-with-circuitpython/advanced-using-pio-to-drive-neopixels-in-the-background
byte_count = bpp * num_leds
bit_count = byte_count * 8

# array of 32bit integers, with header and trailer at the beginning and end
self.pixels = array.array("I", [0] * (num_leds + 2))
# header - num of bits in the data stream
self.header = bit_count - 1
# trailer - delay at the end (12.8 Mhz clk -> 1 period = 7.8125e-8, 3840 * 7.8125e-8 = 0.0003s delay)
self.trailer = 3840
self.pixels[0] = self.header
self.pixels[-1] = self.trailer

def brightness(self, brightness=None):
"""
Set the overall value to adjust brightness when updating leds
Expand Down Expand Up @@ -195,9 +229,11 @@ def set_pixel(self, pixel_num, rgb_w, how_bright=None):
# set some subset, if pixel_num is a slice:
if type(pixel_num) is slice:
for i in range(*pixel_num.indices(self.num_leds)):
self.pixels[i] = pix_value
# offset of 1 due to header
self.pixels[i + 1] = pix_value
else:
self.pixels[pixel_num] = pix_value
# offset of 1 due to header
self.pixels[pixel_num + 1] = pix_value

def get_pixel(self, pixel_num):
"""
Expand All @@ -206,7 +242,9 @@ def get_pixel(self, pixel_num):
:param pixel_num: Index of pixel to be set
:return rgb_w: Tuple of form (r, g, b) or (r, g, b, w) representing color to be used
"""
balance = self.pixels[pixel_num]
# offset of 1 due to header
balance = self.pixels[pixel_num + 1]

sh_R, sh_G, sh_B, sh_W = self.shift
if self.W_in_mode:
w = (balance >> sh_W) & 255
Expand Down Expand Up @@ -317,7 +355,10 @@ def rotate_left(self, num_of_pixels=None):
"""
if num_of_pixels is None:
num_of_pixels = 1
self.pixels = self.pixels[num_of_pixels:] + self.pixels[:num_of_pixels]
# offset of 1 due to header
num_of_pixels += 1
#self.pixels = self.pixels[num_of_pixels:] + self.pixels[:num_of_pixels]
self.pixels = array.array("I", [self.pixels[0]] + list(self.pixels[num_of_pixels:-1]) + list(self.pixels[1:num_of_pixels]) + [self.pixels[-1]])

def rotate_right(self, num_of_pixels=None):
"""
Expand All @@ -328,23 +369,21 @@ def rotate_right(self, num_of_pixels=None):
"""
if num_of_pixels is None:
num_of_pixels = 1
# offset of 1 due to header
num_of_pixels += 1
num_of_pixels = -1 * num_of_pixels
self.pixels = self.pixels[num_of_pixels:] + self.pixels[:num_of_pixels]
#self.pixels = self.pixels[num_of_pixels:] + self.pixels[:num_of_pixels]
self.pixels = array.array("I", [self.pixels[0]] + list(self.pixels[num_of_pixels:-1]) + list(self.pixels[1:num_of_pixels]) + [self.pixels[-1]])

def show(self):
"""
Send data to led-strip, making all changes on leds have an effect.
This method should be used after every method that changes the state of leds or after a chain of changes.
:return: None
"""
# If mode is RGB, we cut 8 bits of, otherwise we keep all 32
cut = 8
if self.W_in_mode:
cut = 0

self.sm.put(self.pixels, cut)
# put entire pixel data along with header and trailer into TX FIFO
self.sm.put(memoryview(self.pixels))

time.sleep(self.delay)

def fill(self, rgb_w, how_bright=None):
"""
Expand All @@ -363,4 +402,6 @@ def clear(self):

:return: None
"""
self.pixels = array.array("I", [0] * self.num_leds)
self.pixels = array.array("I", [0] * (self.num_leds + 2))
self.pixels[0] = self.header
self.pixels[-1] = self.trailer