lora-irrigation/blinkled/genseq.py

from encdec8b10b import EncDec8B10B

a = b'Hello, this is a test of encoding.'

coder = EncDec8B10B()

encoded = coder.encode(EncDec8B10B.COMMA) + coder.encode(a)
print('8b10b encoded:', repr(encoded))

decoder = EncDec8B10B()

print(repr(decoder.decode(encoded)))
print('test decode:', repr(decoder.decode('')))

def jm3coder(bits, lastlvl=0):
	'''Takes in a string of bits, and outputs a trinary level.
	It is guaranteed that no two outputs repeat allowing for
	easy clock recovery as long as the sampling rate is faster
	than output rate.  (e.g. 30Hz (33.3ms) sampling of a 29Hz
	(34.5ms) signal.

	Note that this does not do sync, so something like an 8b10b
	encoder should be used on top of this, and then transmit three
	dummy bits at the begining as the decoder.  The three will
	cycle through all three states help ensuring level detection

	An optional paramter of lastlvl can be provided, which is
	the previous signal level transmitted.'''

	r = []
	for i in bits:
		v = int(i, 2)
		lastlvl = (lastlvl + 1 + v) % 3
		r.append('%d' % lastlvl)

	return ''.join(r)

encoded = jm3coder('000' + encoded)

print('jm3coded:', repr(encoded))

# make a "stretched" bit string
stretched = ''.join(encoded[i:i + 50] + encoded[i:i + 50][-1] for i in range(0, len(encoded), 50))
print('stretched:', repr(stretched))

def jm3decoder(trits, lastlvl=0):
	'''Decodes a string encoded w/ jm3coder.

	lastlvl should/must be provided which is the last rx'd level
	(it must be 0, 1 or 2).
	'''

	lookup = {
		(0, 1): 0,
		(0, 2): 1,
		(1, 2): 0,
		(1, 0): 1,
		(2, 0): 0,
		(2, 1): 1,
	}
	r = []
	for i in trits:
		lvl = int(i, 3)
		if lvl == lastlvl:
			continue

		r.append('%d' % lookup[(lastlvl, lvl)])
		#r.append('%d' % ((lvl - lastlvl + 2) % 3))
		lastlvl = lvl

	return ''.join(r)

decoder = EncDec8B10B()

stretched = jm3decoder(stretched)

print(repr(stretched))

print(repr(decoder.decode(stretched)))
print(repr(decoder.decode('')))

print('done')