## along with this program; if not, see <http://www.gnu.org/licenses/>.
##
+# Implementor's notes on the wire format:
+# - World Semi vendor, (Adafruit copy of the) datasheet
+# https://cdn-shop.adafruit.com/datasheets/WS2812.pdf
+# - reset pulse is 50us (or more) of low pin level
+# - 24bits per WS281x item, 3x 8bits, MSB first, GRB sequence,
+# cascaded WS281x items, all "excess bits" are passed through
+# - bit time starts with high period, continues with low period,
+# high to low periods' ratio determines bit value, datasheet
+# mentions 0.35us/0.8us for value 0, 0.7us/0.6us for value 1
+# (huge 150ns tolerances, un-even 0/1 value length, hmm)
+# - experience suggests the timing "is variable", rough estimation
+# often is good enough, microcontroller firmware got away with
+# four quanta per bit time, or even with three quanta (30%/60%),
+# Adafruit learn article suggests 1.2us total and 0.4/0.8 or
+# 0.8/0.4 high/low parts, four quanta are easier to handle when
+# the bit stream is sent via SPI to avoid MCU bit banging and its
+# inaccurate timing (when interrupts are used in the firmware)
+# - RGBW datasheet (Adafruit copy) for SK6812
+# https://cdn-shop.adafruit.com/product-files/2757/p2757_SK6812RGBW_REV01.pdf
+# also 1.2us total, shared across 0.3/0.9 for 0, 0.6/0.6 for 1,
+# 80us reset pulse, R8/G8/B8/W8 format per 32bits
+# - WS2815, RGB LED, uses GRB wire format, 280us RESET pulse width
+# - more vendors and models available and in popular use,
+# suggests "one third" or "two thirds" ratio would be most robust,
+# sample "a little before" the bit half? reset pulse width may need
+# to become an option? matrices and/or fast refresh environments
+# may want to experiment with back to back pixel streams
+
import sigrokdecode as srd
from common.srdhelper import bitpack_msb
class SamplerateError(Exception):
pass
-( ANN_BIT, ANN_RESET, ANN_RGB, ) = range(3)
+class DecoderError(Exception):
+ pass
+
+(
+ ANN_BIT, ANN_RESET, ANN_RGB,
+ ANN_COMP_R, ANN_COMP_G, ANN_COMP_B, ANN_COMP_W,
+) = range(7)
class Decoder(srd.Decoder):
api_version = 3
('bit', 'Bit'),
('reset', 'RESET'),
('rgb', 'RGB'),
+ ('r', 'R'),
+ ('g', 'G'),
+ ('b', 'B'),
+ ('w', 'W'),
)
annotation_rows = (
('bits', 'Bits', (ANN_BIT, ANN_RESET,)),
+ ('rgb-comps', 'RGB components', (ANN_COMP_R, ANN_COMP_G, ANN_COMP_B, ANN_COMP_W,)),
('rgb-vals', 'RGB values', (ANN_RGB,)),
)
options = (
- {'id': 'type', 'desc': 'RGB or RGBW', 'default': 'RGB',
- 'values': ('RGB', 'RGBW')},
+ {'id': 'wireorder', 'desc': 'colour components order (wire)',
+ 'default': 'GRB',
+ 'values': ('BGR', 'BRG', 'GBR', 'GRB', 'RBG', 'RGB', 'RWBG', 'RGBW')},
+ {'id': 'textorder', 'desc': 'components output order (text)',
+ 'default': 'RGB[W]', 'values': ('wire', 'RGB[W]', 'RGB', 'RGBW', 'RGWB')},
)
def __init__(self):
def handle_bits(self):
if len(self.bits) < self.need_bits:
return
- grb = bitpack_msb(self.bits, 0)
- if self.options['type'] == 'RGB':
- rgb = (grb & 0xff0000) >> 8 | (grb & 0x00ff00) << 8 | (grb & 0x0000ff)
- text = '#{:06x}'.format(rgb)
- else:
- rgb = (grb & 0xff0000) >> 8 | (grb & 0x00ff00) << 8 | (grb & 0xff0000ff)
- text = '#{:08x}'.format(rgb)
ss_packet, es_packet = self.bits[0][1], self.bits[-1][2]
- self.putg(ss_packet, es_packet, ANN_RGB, [text])
+ r, g, b, w = 0, 0, 0, None
+ comps = []
+ for i, c in enumerate(self.wireformat):
+ first_idx, after_idx = 8 * i, 8 * i + 8
+ comp_bits = self.bits[first_idx:after_idx]
+ comp_ss, comp_es = comp_bits[0][1], comp_bits[-1][2]
+ comp_value = bitpack_msb(comp_bits, 0)
+ comp_text = '{:02x}'.format(comp_value)
+ comp_ann = {
+ 'r': ANN_COMP_R, 'g': ANN_COMP_G,
+ 'b': ANN_COMP_B, 'w': ANN_COMP_W,
+ }.get(c.lower(), None)
+ comp_item = (comp_ss, comp_es, comp_ann, comp_value, comp_text)
+ comps.append(comp_item)
+ if c.lower() == 'r':
+ r = comp_value
+ elif c.lower() == 'g':
+ g = comp_value
+ elif c.lower() == 'b':
+ b = comp_value
+ elif c.lower() == 'w':
+ w = comp_value
+ wt = '' if w is None else '{:02x}'.format(w)
+ if self.textformat == 'wire':
+ rgb_text = '#' + ''.join([c[-1] for c in comps])
+ else:
+ rgb_text = self.textformat.format(r = r, g = g, b = b, w = w, wt = wt)
+ for ss_comp, es_comp, cls_comp, value_comp, text_comp in comps:
+ self.putg(ss_comp, es_comp, cls_comp, [text_comp])
+ if rgb_text:
+ self.putg(ss_packet, es_packet, ANN_RGB, [rgb_text])
self.bits.clear()
def handle_bit(self, ss, es, value, ann_late = False):
def decode(self):
if not self.samplerate:
raise SamplerateError('Cannot decode without samplerate.')
- self.need_bits = len(self.options['type']) * 8
+
+ # Preprocess options here, to simplify logic which executes
+ # much later in loops while settings have the same values.
+ wireorder = self.options['wireorder'].lower()
+ self.wireformat = [c for c in wireorder if c in 'rgbw']
+ self.need_bits = len(self.wireformat) * 8
+ textorder = self.options['textorder'].lower()
+ if textorder == 'wire':
+ self.textformat = 'wire'
+ elif textorder == 'rgb[w]':
+ self.textformat = '#{r:02x}{g:02x}{b:02x}{wt:s}'
+ else:
+ self.textformat = {
+ # "Obvious" permutations of R/G/B.
+ 'bgr': '#{b:02x}{g:02x}{r:02x}',
+ 'brg': '#{b:02x}{r:02x}{g:02x}',
+ 'gbr': '#{g:02x}{b:02x}{r:02x}',
+ 'grb': '#{g:02x}{r:02x}{b:02x}',
+ 'rbg': '#{r:02x}{b:02x}{g:02x}',
+ 'rgb': '#{r:02x}{g:02x}{b:02x}',
+ # RGB plus White. Only one of them useful?
+ 'rgbw': '#{r:02x}{g:02x}{b:02x}{w:02x}',
+ # Weird RGBW permutation for compatibility to test case.
+ # Neither used RGBW nor the 'wire' order. Obsolete now?
+ 'rgwb': '#{r:02x}{g:02x}{w:02x}{b:02x}',
+ }.get(textorder, None)
+ if self.textformat is None:
+ raise DecoderError('Unsupported text output format.')
# Either check for edges which communicate bit values, or for
# long periods of idle level which represent a reset pulse.
projects / libsigrokdecode.git / blobdiff