diff options
Diffstat (limited to 'decoders/usb')
| -rw-r--r-- | decoders/usb/Makefile.am | 26 | ||||
| -rw-r--r-- | decoders/usb/__init__.py | 22 | ||||
| -rw-r--r-- | decoders/usb/usb.py | 193 |
3 files changed, 241 insertions, 0 deletions
diff --git a/decoders/usb/Makefile.am b/decoders/usb/Makefile.am new file mode 100644 index 0000000..f758e06 --- /dev/null +++ b/decoders/usb/Makefile.am @@ -0,0 +1,26 @@ +## +## This file is part of the sigrok project. +## +## Copyright (C) 2012 Uwe Hermann <uwe@hermann-uwe.de> +## +## 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 +## + +pkgdatadir = $(DECODERS_DIR)/usb + +dist_pkgdata_DATA = __init__.py usb.py + +CLEANFILES = *.pyc + diff --git a/decoders/usb/__init__.py b/decoders/usb/__init__.py new file mode 100644 index 0000000..068cadf --- /dev/null +++ b/decoders/usb/__init__.py @@ -0,0 +1,22 @@ +## +## This file is part of the sigrok project. +## +## Copyright (C) 2012 Uwe Hermann <uwe@hermann-uwe.de> +## +## 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 +## + +from .usb import * + diff --git a/decoders/usb/usb.py b/decoders/usb/usb.py new file mode 100644 index 0000000..073fe01 --- /dev/null +++ b/decoders/usb/usb.py @@ -0,0 +1,193 @@ +## +## 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 + |