X-Git-Url: https://sigrok.org/gitweb/?p=libsigrokdecode.git;a=blobdiff_plain;f=decoders%2Fspi%2Fpd.py;h=e00235e2a8bff976654d13484c8a569665ec44db;hp=10857866f4cad8ebdc41fe58600cdb688b8d6420;hb=0309c15a6990f57fbbb27d6a77957b1282163f06;hpb=24c74fd30fb161837c5f8b01baf3c0fe2dfa4ed5 diff --git a/decoders/spi/pd.py b/decoders/spi/pd.py index 1085786..e00235e 100644 --- a/decoders/spi/pd.py +++ b/decoders/spi/pd.py @@ -1,8 +1,8 @@ ## -## This file is part of the sigrok project. +## This file is part of the libsigrokdecode project. ## ## Copyright (C) 2011 Gareth McMullin -## Copyright (C) 2012 Uwe Hermann +## Copyright (C) 2012-2013 Uwe Hermann ## ## 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 @@ -23,6 +23,26 @@ import sigrokdecode as srd +''' +Protocol output format: + +SPI packet: +[, , ] + +Commands: + - 'DATA': contains the MISO data, contains the MOSI data. + The data is _usually_ 8 bits (but can also be fewer or more bits). + Both data items are Python numbers, not strings. + - 'CS CHANGE': is the old CS# pin value, is the new value. + Both data items are Python numbers (0/1), not strings. + +Examples: + ['CS-CHANGE', 1, 0] + ['DATA', 0xff, 0x3a] + ['DATA', 0x65, 0x00] + ['CS-CHANGE', 0, 1] +''' + # Key: (CPOL, CPHA). Value: SPI mode. # Clock polarity (CPOL) = 0/1: Clock is low/high when inactive. # Clock phase (CPHA) = 0/1: Data is valid on the leading/trailing clock edge. @@ -33,9 +53,6 @@ spi_mode = { (1, 1): 3, # Mode 3 } -# Annotation formats -ANN_HEX = 0 - class Decoder(srd.Decoder): api_version = 1 id = 'spi' @@ -51,116 +68,147 @@ class Decoder(srd.Decoder): {'id': 'mosi', 'name': 'MOSI', 'desc': 'SPI MOSI line (Master out, slave in)'}, {'id': 'sck', 'name': 'CLK', 'desc': 'SPI clock line'}, - {'id': 'cs', 'name': 'CS#', 'desc': 'SPI CS (chip select) line'}, ] - optional_probes = [] # TODO + optional_probes = [ + {'id': 'cs', 'name': 'CS#', 'desc': 'SPI chip-select line'}, + ] options = { 'cs_polarity': ['CS# polarity', 'active-low'], 'cpol': ['Clock polarity', 0], 'cpha': ['Clock phase', 0], 'bitorder': ['Bit order within the SPI data', 'msb-first'], 'wordsize': ['Word size of SPI data', 8], # 1-64? + 'format': ['Data format', 'hex'], } annotations = [ - ['Hex', 'SPI data bytes in hex format'], + ['MISO/MOSI data', 'MISO/MOSI SPI data'], + ['MISO data', 'MISO SPI data'], + ['MOSI data', 'MOSI SPI data'], + ['Warnings', 'Human-readable warnings'], ] def __init__(self): + self.samplerate = None self.oldsck = 1 self.bitcount = 0 self.mosidata = 0 self.misodata = 0 - self.bytesreceived = 0 + self.startsample = -1 self.samplenum = -1 self.cs_was_deasserted_during_data_word = 0 self.oldcs = -1 self.oldpins = None + self.state = 'IDLE' - def start(self, metadata): - self.out_proto = self.add(srd.OUTPUT_PROTO, 'spi') - self.out_ann = self.add(srd.OUTPUT_ANN, 'spi') + def metadata(self, key, value): + if key == srd.SRD_CONF_SAMPLERATE: + self.samplerate = value - def report(self): - return 'SPI: %d bytes received' % self.bytesreceived - - def decode(self, ss, es, data): - # TODO: Either MISO or MOSI could be optional. CS# is optional. - for (self.samplenum, pins) in data: - - # Ignore identical samples early on (for performance reasons). - if self.oldpins == pins: - continue - self.oldpins, (miso, mosi, sck, cs) = pins, pins + def start(self): + self.out_proto = self.register(srd.OUTPUT_PYTHON) + self.out_ann = self.register(srd.OUTPUT_ANN) + self.out_bitrate = self.register(srd.OUTPUT_META, + meta=(int, 'Bitrate', 'Bitrate during transfers')) - if self.oldcs != cs: - # Send all CS# pin value changes. - self.put(self.samplenum, self.samplenum, self.out_proto, - ['CS-CHANGE', self.oldcs, cs]) - self.put(self.samplenum, self.samplenum, self.out_ann, - [0, ['CS-CHANGE: %d->%d' % (self.oldcs, cs)]]) - self.oldcs = cs + def putpw(self, data): + self.put(self.startsample, self.samplenum, self.out_proto, data) - # Ignore sample if the clock pin hasn't changed. - if sck == self.oldsck: - continue + def putw(self, data): + self.put(self.startsample, self.samplenum, self.out_ann, data) - self.oldsck = sck - - # Sample data on rising/falling clock edge (depends on mode). - mode = spi_mode[self.options['cpol'], self.options['cpha']] - if mode == 0 and sck == 0: # Sample on rising clock edge - continue - elif mode == 1 and sck == 1: # Sample on falling clock edge - continue - elif mode == 2 and sck == 1: # Sample on falling clock edge - continue - elif mode == 3 and sck == 0: # Sample on rising clock edge - continue - - # If this is the first bit, save its sample number. - if self.bitcount == 0: - self.start_sample = self.samplenum + def handle_bit(self, miso, mosi, sck, cs): + # If this is the first bit, save its sample number. + if self.bitcount == 0: + self.startsample = self.samplenum + if self.have_cs: active_low = (self.options['cs_polarity'] == 'active-low') deasserted = cs if active_low else not cs if deasserted: self.cs_was_deasserted_during_data_word = 1 - ws = self.options['wordsize'] - - # Receive MOSI bit into our shift register. - if self.options['bitorder'] == 'msb-first': - self.mosidata |= mosi << (ws - 1 - self.bitcount) - else: - self.mosidata |= mosi << self.bitcount - - # Receive MISO bit into our shift register. - if self.options['bitorder'] == 'msb-first': - self.misodata |= miso << (ws - 1 - self.bitcount) - else: - self.misodata |= miso << self.bitcount + ws = self.options['wordsize'] + + # Receive MOSI bit into our shift register. + if self.options['bitorder'] == 'msb-first': + self.mosidata |= mosi << (ws - 1 - self.bitcount) + else: + self.mosidata |= mosi << self.bitcount + + # Receive MISO bit into our shift register. + if self.options['bitorder'] == 'msb-first': + self.misodata |= miso << (ws - 1 - self.bitcount) + else: + self.misodata |= miso << self.bitcount + + self.bitcount += 1 + + # Continue to receive if not enough bits were received, yet. + if self.bitcount != ws: + return + + # Pass MOSI and MISO to the next PD up the stack + self.putpw(['DATA', self.mosidata, self.misodata]) + + # Annotations + self.putw([0, ['%02X/%02X' % (self.mosidata, self.misodata)]]) + self.putw([1, ['%02X' % self.misodata]]) + self.putw([2, ['%02X' % self.mosidata]]) + + # Meta bitrate + elapsed = 1 / float(self.samplerate) * (self.samplenum - self.startsample + 1) + bitrate = int(1 / elapsed * self.options['wordsize']) + self.put(self.startsample, self.samplenum, self.out_bitrate, bitrate) + + if self.cs_was_deasserted_during_data_word: + self.putw([3, ['CS# was deasserted during this data word!']]) + + # Reset decoder state. + self.mosidata = self.misodata = self.bitcount = 0 + + def find_clk_edge(self, miso, mosi, sck, cs): + if self.have_cs and self.oldcs != cs: + # Send all CS# pin value changes. + self.put(self.samplenum, self.samplenum, self.out_proto, + ['CS-CHANGE', self.oldcs, cs]) + self.oldcs = cs + # Reset decoder state when CS# changes (and the CS# pin is used). + self.mosidata = self.misodata = self.bitcount= 0 + + # Ignore sample if the clock pin hasn't changed. + if sck == self.oldsck: + return + + self.oldsck = sck + + # Sample data on rising/falling clock edge (depends on mode). + mode = spi_mode[self.options['cpol'], self.options['cpha']] + if mode == 0 and sck == 0: # Sample on rising clock edge + return + elif mode == 1 and sck == 1: # Sample on falling clock edge + return + elif mode == 2 and sck == 1: # Sample on falling clock edge + return + elif mode == 3 and sck == 0: # Sample on rising clock edge + return + + # Found the correct clock edge, now get the SPI bit(s). + self.handle_bit(miso, mosi, sck, cs) - self.bitcount += 1 + def decode(self, ss, es, data): + if self.samplerate is None: + raise Exception("Cannot decode without samplerate.") + # TODO: Either MISO or MOSI could be optional. CS# is optional. + for (self.samplenum, pins) in data: - # Continue to receive if not enough bits were received, yet. - if self.bitcount != ws: + # Ignore identical samples early on (for performance reasons). + if self.oldpins == pins: continue + self.oldpins, (miso, mosi, sck, cs) = pins, pins + self.have_cs = (cs in (0, 1)) - self.put(self.start_sample, self.samplenum, self.out_proto, - ['DATA', self.mosidata, self.misodata]) - self.put(self.start_sample, self.samplenum, self.out_ann, - [ANN_HEX, ['MOSI: 0x%02x, MISO: 0x%02x' % (self.mosidata, - self.misodata)]]) - - if self.cs_was_deasserted_during_data_word: - self.put(self.start_sample, self.samplenum, self.out_ann, - [ANN_HEX, ['WARNING: CS# was deasserted during this ' - 'SPI data byte!']]) - - # Reset decoder state. - self.mosidata = 0 - self.misodata = 0 - self.bitcount = 0 - - # Keep stats for summary. - self.bytesreceived += 1 + # State machine. + if self.state == 'IDLE': + self.find_clk_edge(miso, mosi, sck, cs) + else: + raise Exception('Invalid state: %s' % self.state)