import sigrokdecode as srd
-# States
-SE0, J, K, SE1 = 0, 1, 2, 3
-
-# ...
+# Symbols (used as states of our state machine, too)
syms = {
- (0, 0): SE0,
- (1, 0): J,
- (0, 1): K,
- (1, 1): SE1,
+ (0, 0): 'SE0',
+ (1, 0): 'J',
+ (0, 1): 'K',
+ (1, 1): 'SE1',
}
# ...
name = 'USB'
longname = 'Universal Serial Bus'
desc = 'Universal Serial Bus'
- longdesc = '...longdesc...'
license = 'gplv2+'
inputs = ['logic']
outputs = ['usb']
pass
def start(self, metadata):
- self.rate = metadata['samplerate']
+ self.samplerate = metadata['samplerate']
# self.out_proto = self.add(srd.OUTPUT_PROTO, 'usb')
self.out_ann = self.add(srd.OUTPUT_ANN, 'usb')
- if self.rate < 48000000:
- raise Exception('Sample rate (%d) not sufficient for USB '
- 'decoding, need at least 48MHz' % self.rate)
+ if self.samplerate < 48000000:
+ raise Exception('Samplerate (%d) not sufficient for USB '
+ 'decoding, need at least 48MHz' % self.samplerate)
# Initialise decoder state.
- self.sym = J
+ self.sym = 'J'
self.scount = 0
self.packet = ''
continue
# How many bits since the last transition?
- if self.packet != '' or self.sym != J:
- bitcount = int((self.scount - 1) * 12000000 / self.rate)
+ if self.packet != '' or self.sym != 'J':
+ bitcount = int((self.scount - 1) * 12000000 / self.samplerate)
else:
bitcount = 0
- if self.sym == SE0:
+ if self.sym == 'SE0':
if bitcount == 1:
# End-Of-Packet (EOP)
self.put(0, 0, self.out_ann,
self.packet += '1' * bitcount
# Handle bit stuffing.
- if bitcount < 6 and sym != SE0:
+ if bitcount < 6 and sym != 'SE0':
self.packet += '0'
elif bitcount > 6:
self.put(0, 0, self.out_ann, [0, ['BIT STUFF ERROR']])