+++ /dev/null
-##
-## This file is part of the sigrok project.
-##
-## Copyright (C) 2011 Gareth McMullin <gareth@blacksphere.co.nz>
-##
-## This program is free software; you can redistribute it and/or modify
-## it under the terms of the GNU General Public License as published by
-## the Free Software Foundation; either version 2 of the License, or
-## (at your option) any later version.
-##
-## This program is distributed in the hope that it will be useful,
-## but WITHOUT ANY WARRANTY; without even the implied warranty of
-## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-## GNU General Public License for more details.
-##
-## You should have received a copy of the GNU General Public License
-## along with this program; if not, write to the Free Software
-## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
-##
-
-#
-# USB Full-speed protocol decoder
-#
-# Full-speed USB signalling consists of two signal lines, both driven at 3.3V
-# logic levels. The signals are DP (D+) and DM (D-), and normally operate in
-# differential mode.
-# The state where DP=1,DM=0 is J, the state DP=0,DM=1 is K.
-# A state SE0 is defined where DP=DM=0. This common mode signal is used to
-# signal a reset or end of packet.
-#
-# Data transmitted on the USB is encoded with NRZI. A transition from J to K
-# or vice-versa indicates a logic 0, while no transition indicates a logic 1.
-# If 6 ones are transmitted consecutively, a zero is inserted to force a
-# transition. This is known as bit stuffing. Data is transferred at a rate
-# of 12Mbit/s. The SE0 transmitted to signal an end-of-packet is two bit
-# intervals long.
-#
-# Details:
-# https://en.wikipedia.org/wiki/USB
-# http://www.usb.org/developers/docs/
-#
-
-import sigrokdecode as srd
-
-# States
-SE0, J, K, SE1 = 0, 1, 2, 3
-
-# ...
-syms = {
- (0, 0): SE0,
- (1, 0): J,
- (0, 1): K,
- (1, 1): SE1,
-}
-
-# ...
-pids = {
- '10000111': 'OUT', # Tokens
- '10010110': 'IN',
- '10100101': 'SOF',
- '10110100': 'SETUP',
- '11000011': 'DATA0', # Data
- '11010010': 'DATA1',
- '01001011': 'ACK', # Handshake
- '01011010': 'NAK',
- '01111000': 'STALL',
- '01101001': 'NYET',
-}
-
-def bitstr_to_num(bitstr):
- if not bitstr:
- return 0
- l = list(bitstr)
- l.reverse()
- return int(''.join(l), 2)
-
-def packet_decode(packet):
- sync = packet[:8]
- pid = packet[8:16]
- pid = pids.get(pid, pid)
-
- # Remove CRC.
- if pid in ('OUT', 'IN', 'SOF', 'SETUP'):
- data = packet[16:-5]
- if pid == 'SOF':
- data = str(bitstr_to_num(data))
- else:
- dev = bitstr_to_num(data[:7])
- ep = bitstr_to_num(data[7:])
- data = 'DEV %d EP %d' % (dev, ep)
-
- elif pid in ('DATA0', 'DATA1'):
- data = packet[16:-16]
- tmp = ''
- while data:
- tmp += '%02x ' % bitstr_to_num(data[:8])
- data = data[8:]
- data = tmp
- else:
- data = packet[16:]
-
- if sync != '00000001':
- return 'SYNC INVALID!'
-
- return pid + ' ' + data
-
-class Decoder(srd.Decoder):
- id = 'usb'
- name = 'USB'
- longname = 'Universal Serial Bus'
- desc = 'Universal Serial Bus'
- longdesc = '...longdesc...'
- license = 'gplv2+'
- inputs = ['logic']
- outputs = ['usb']
- probes = [
- {'id': 'dp', 'name': 'D+', 'desc': 'USB D+ signal'},
- {'id': 'dm', 'name': 'D-', 'desc': 'USB D- signal'},
- ]
- options = {}
- annotations = [
- ['TODO', 'TODO']
- ]
-
- def __init__(self):
- pass
-
- def start(self, metadata):
- self.rate = 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 not sufficient for USB decoding')
-
- # Initialise decoder state.
- self.sym = J
- self.scount = 0
- self.packet = ''
-
- def decode(self, ss, es, data):
-
- # FIXME
- # for (samplenum, (dp, dm, x, y, z, a)) in data:
- for (samplenum, (dm, dp)) in data:
-
- self.scount += 1
-
- sym = syms[dp, dm]
-
- # ...
- if sym == self.sym:
- continue
-
- if self.scount == 1:
- # We ignore single sample width pulses.
- # I sometimes get these with the OLS.
- self.sym = sym
- self.scount = 0
- continue
-
- # How many bits since the last transition?
- if self.packet != '' or self.sym != J:
- bitcount = int((self.scount - 1) * 12000000 / self.rate)
- else:
- bitcount = 0
-
- if self.sym == SE0:
- if bitcount == 1:
- # End-Of-Packet (EOP)
- self.put(0, 0, self.out_ann,
- [0, [packet_decode(self.packet), self.packet]])
- else:
- # Longer than EOP, assume reset.
- self.put(0, 0, self.out_ann, [0, ['RESET']])
- self.scount = 0
- self.sym = sym
- self.packet = ''
- continue
-
- # Add bits to the packet string.
- self.packet += '1' * bitcount
-
- # Handle bit stuffing.
- if bitcount < 6 and sym != SE0:
- self.packet += '0'
- elif bitcount > 6:
- self.put(0, 0, self.out_ann, [0, ['BIT STUFF ERROR']])
-
- self.scount = 0
- self.sym = sym
-
projects / libsigrokdecode.git / blobdiff