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author | Uwe Hermann <uwe@hermann-uwe.de> | 2012-11-21 22:43:02 +0100 |
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committer | Uwe Hermann <uwe@hermann-uwe.de> | 2012-11-24 20:21:19 +0100 |
commit | 24c74fd30fb161837c5f8b01baf3c0fe2dfa4ed5 (patch) | |
tree | 43d0c24c6a18e824d9d66a390bad9cff3aa081af /decoders/i2c/i2c.py | |
parent | 23f999aa996e54cd73cb54d5e254d1445d65847d (diff) | |
download | libsigrokdecode-24c74fd30fb161837c5f8b01baf3c0fe2dfa4ed5.tar.gz libsigrokdecode-24c74fd30fb161837c5f8b01baf3c0fe2dfa4ed5.zip |
All PDs: Name the files pd.py consistently.
The Python module name is determined by the directory name (e.g. dcf77),
the *.py file names in that directory don't matter and can be kept
consistent.
Diffstat (limited to 'decoders/i2c/i2c.py')
-rw-r--r-- | decoders/i2c/i2c.py | 240 |
1 files changed, 0 insertions, 240 deletions
diff --git a/decoders/i2c/i2c.py b/decoders/i2c/i2c.py deleted file mode 100644 index 53321eb..0000000 --- a/decoders/i2c/i2c.py +++ /dev/null @@ -1,240 +0,0 @@ -## -## This file is part of the sigrok project. -## -## Copyright (C) 2010-2011 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 -## - -# I2C protocol decoder - -# TODO: Look into arbitration, collision detection, clock synchronisation, etc. -# TODO: Handle clock stretching. -# TODO: Handle combined messages / repeated START. -# TODO: Implement support for 7bit and 10bit slave addresses. -# TODO: Implement support for inverting SDA/SCL levels (0->1 and 1->0). -# TODO: Implement support for detecting various bus errors. -# TODO: I2C address of slaves. -# TODO: Handle multiple different I2C devices on same bus -# -> we need to decode multiple protocols at the same time. - -import sigrokdecode as srd - -# Annotation feed formats -ANN_SHIFTED = 0 -ANN_SHIFTED_SHORT = 1 -ANN_RAW = 2 - -# Values are verbose and short annotation, respectively. -proto = { - 'START': ['START', 'S'], - 'START REPEAT': ['START REPEAT', 'Sr'], - 'STOP': ['STOP', 'P'], - 'ACK': ['ACK', 'A'], - 'NACK': ['NACK', 'N'], - 'ADDRESS READ': ['ADDRESS READ', 'AR'], - 'ADDRESS WRITE': ['ADDRESS WRITE', 'AW'], - 'DATA READ': ['DATA READ', 'DR'], - 'DATA WRITE': ['DATA WRITE', 'DW'], -} - -class Decoder(srd.Decoder): - api_version = 1 - id = 'i2c' - name = 'I2C' - longname = 'Inter-Integrated Circuit' - desc = 'Two-wire, multi-master, serial bus.' - license = 'gplv2+' - inputs = ['logic'] - outputs = ['i2c'] - probes = [ - {'id': 'scl', 'name': 'SCL', 'desc': 'Serial clock line'}, - {'id': 'sda', 'name': 'SDA', 'desc': 'Serial data line'}, - ] - optional_probes = [] - options = { - 'addressing': ['Slave addressing (in bits)', 7], # 7 or 10 - } - annotations = [ - # ANN_SHIFTED - ['7-bit shifted hex', - 'Read/write bit shifted out from the 8-bit I2C slave address'], - # ANN_SHIFTED_SHORT - ['7-bit shifted hex (short)', - 'Read/write bit shifted out from the 8-bit I2C slave address'], - # ANN_RAW - ['Raw hex', 'Unaltered raw data'], - ] - - def __init__(self, **kwargs): - self.startsample = -1 - self.samplenum = None - self.bitcount = 0 - self.databyte = 0 - self.wr = -1 - self.is_repeat_start = 0 - self.state = 'FIND START' - self.oldscl = None - self.oldsda = None - self.oldpins = None - - def start(self, metadata): - self.out_proto = self.add(srd.OUTPUT_PROTO, 'i2c') - self.out_ann = self.add(srd.OUTPUT_ANN, 'i2c') - - def report(self): - pass - - def is_start_condition(self, scl, sda): - # START condition (S): SDA = falling, SCL = high - if (self.oldsda == 1 and sda == 0) and scl == 1: - return True - return False - - def is_data_bit(self, scl, sda): - # Data sampling of receiver: SCL = rising - if self.oldscl == 0 and scl == 1: - return True - return False - - def is_stop_condition(self, scl, sda): - # STOP condition (P): SDA = rising, SCL = high - if (self.oldsda == 0 and sda == 1) and scl == 1: - return True - return False - - def found_start(self, scl, sda): - self.startsample = self.samplenum - - cmd = 'START REPEAT' if (self.is_repeat_start == 1) else 'START' - self.put(self.out_proto, [cmd, None]) - self.put(self.out_ann, [ANN_SHIFTED, [proto[cmd][0]]]) - self.put(self.out_ann, [ANN_SHIFTED_SHORT, [proto[cmd][1]]]) - - self.state = 'FIND ADDRESS' - self.bitcount = self.databyte = 0 - self.is_repeat_start = 1 - self.wr = -1 - - # Gather 8 bits of data plus the ACK/NACK bit. - def found_address_or_data(self, scl, sda): - # Address and data are transmitted MSB-first. - self.databyte <<= 1 - self.databyte |= sda - - if self.bitcount == 0: - self.startsample = self.samplenum - - # Return if we haven't collected all 8 + 1 bits, yet. - self.bitcount += 1 - if self.bitcount != 8: - return - - # We triggered on the ACK/NACK bit, but won't report that until later. - self.startsample -= 1 - - # Send raw output annotation before we start shifting out - # read/write and ACK/NACK bits. - self.put(self.out_ann, [ANN_RAW, ['0x%.2x' % self.databyte]]) - - if self.state == 'FIND ADDRESS': - # The READ/WRITE bit is only in address bytes, not data bytes. - self.wr = 0 if (self.databyte & 1) else 1 - d = self.databyte >> 1 - elif self.state == 'FIND DATA': - d = self.databyte - - if self.state == 'FIND ADDRESS' and self.wr == 1: - cmd = 'ADDRESS WRITE' - elif self.state == 'FIND ADDRESS' and self.wr == 0: - cmd = 'ADDRESS READ' - elif self.state == 'FIND DATA' and self.wr == 1: - cmd = 'DATA WRITE' - elif self.state == 'FIND DATA' and self.wr == 0: - cmd = 'DATA READ' - - self.put(self.out_proto, [cmd, d]) - self.put(self.out_ann, [ANN_SHIFTED, [proto[cmd][0], '0x%02x' % d]]) - self.put(self.out_ann, [ANN_SHIFTED_SHORT, [proto[cmd][1], '0x%02x' % d]]) - - # Done with this packet. - self.startsample = -1 - self.bitcount = self.databyte = 0 - self.state = 'FIND ACK' - - def get_ack(self, scl, sda): - self.startsample = self.samplenum - ack_bit = 'NACK' if (sda == 1) else 'ACK' - self.put(self.out_proto, [ack_bit, None]) - self.put(self.out_ann, [ANN_SHIFTED, [proto[ack_bit][0]]]) - self.put(self.out_ann, [ANN_SHIFTED_SHORT, [proto[ack_bit][1]]]) - # There could be multiple data bytes in a row, so either find - # another data byte or a STOP condition next. - self.state = 'FIND DATA' - - def found_stop(self, scl, sda): - self.startsample = self.samplenum - self.put(self.out_proto, ['STOP', None]) - self.put(self.out_ann, [ANN_SHIFTED, [proto['STOP'][0]]]) - self.put(self.out_ann, [ANN_SHIFTED_SHORT, [proto['STOP'][1]]]) - - self.state = 'FIND START' - self.is_repeat_start = 0 - self.wr = -1 - - def put(self, output_id, data): - # Inject sample range into the call up to sigrok. - super(Decoder, self).put(self.startsample, self.samplenum, output_id, data) - - def decode(self, ss, es, data): - for (self.samplenum, pins) in data: - - # Ignore identical samples early on (for performance reasons). - if self.oldpins == pins: - continue - self.oldpins, (scl, sda) = pins, pins - - # First sample: Save SCL/SDA value. - if self.oldscl == None: - self.oldscl = scl - self.oldsda = sda - continue - - # TODO: Wait until the bus is idle (SDA = SCL = 1) first? - - # State machine. - if self.state == 'FIND START': - if self.is_start_condition(scl, sda): - self.found_start(scl, sda) - elif self.state == 'FIND ADDRESS': - if self.is_data_bit(scl, sda): - self.found_address_or_data(scl, sda) - elif self.state == 'FIND DATA': - if self.is_data_bit(scl, sda): - self.found_address_or_data(scl, sda) - elif self.is_start_condition(scl, sda): - self.found_start(scl, sda) - elif self.is_stop_condition(scl, sda): - self.found_stop(scl, sda) - elif self.state == 'FIND ACK': - if self.is_data_bit(scl, sda): - self.get_ack(scl, sda) - else: - raise Exception('Invalid state %d' % self.STATE) - - # Save current SDA/SCL values for the next round. - self.oldscl = scl - self.oldsda = sda - |