+##
+## This file is part of the libsigrokdecode project.
+##
+## Copyright (C) 2013 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
+##
+
+# Parallel (sync) bus protocol decoder
+
+import sigrokdecode as srd
+
+'''
+Protocol output format:
+
+Packet:
+[<ptype>, <pdata>]
+
+<ptype>, <pdata>
+ - 'ITEM', [<item>, <itembitsize>]
+ - 'WORD', [<word>, <wordbitsize>, <worditemcount>]
+
+<item>:
+ - A single item (a number). It can be of arbitrary size. The max. number
+ of bits in this item is specified in <itembitsize>.
+
+<itembitsize>:
+ - The size of an item (in bits). For a 4-bit parallel bus this is 4,
+ for a 16-bit parallel bus this is 16, and so on.
+
+<word>:
+ - A single word (a number). It can be of arbitrary size. The max. number
+ of bits in this word is specified in <wordbitsize>. The (exact) number
+ of items in this word is specified in <worditemcount>.
+
+<wordbitsize>:
+ - The size of a word (in bits). For a 2-item word with 8-bit items
+ <wordbitsize> is 16, for a 3-item word with 4-bit items <wordbitsize>
+ is 12, and so on.
+
+<worditemcount>:
+ - The size of a word (in number of items). For a 4-item word (no matter
+ how many bits each item consists of) <worditemcount> is 4, for a 7-item
+ word <worditemcount> is 7, and so on.
+'''
+
+def probe_list(num_probes):
+ l = []
+ for i in range(num_probes):
+ d = {'id': 'd%d' % i, 'name': 'D%d' % i, 'desc': 'Data line %d' % i}
+ l.append(d)
+ return l
+
+class Decoder(srd.Decoder):
+ api_version = 1
+ id = 'parallel'
+ name = 'Parallel'
+ longname = 'Parallel sync bus'
+ desc = 'Generic parallel synchronous bus.'
+ license = 'gplv2+'
+ inputs = ['logic']
+ outputs = ['parallel']
+ probes = [
+ {'id': 'clk', 'name': 'CLK', 'desc': 'Clock line'},
+ ]
+ optional_probes = probe_list(32)
+ options = {
+ 'clock_edge': ['Clock edge to sample on', 'rising'],
+ 'wordsize': ['Word size of the data', 1],
+ 'endianness': ['Endianness of the data', 'little'],
+ 'format': ['Data format', 'hex'],
+ }
+ annotations = [
+ ['items', 'Items'],
+ ['words', 'Words'],
+ ]
+
+ def __init__(self):
+ self.oldclk = None
+ self.items = []
+ self.itemcount = 0
+ self.saved_item = None
+ self.samplenum = 0
+ self.oldpins = None
+ self.ss_item = self.es_item = None
+ self.first = True
+ self.state = 'IDLE'
+
+ def start(self, metadata):
+ self.out_proto = self.add(srd.OUTPUT_PROTO, 'parallel')
+ self.out_ann = self.add(srd.OUTPUT_ANN, 'parallel')
+
+ def report(self):
+ pass
+
+ def putpb(self, data):
+ self.put(self.ss_item, self.es_item, self.out_proto, data)
+
+ def putb(self, data):
+ self.put(self.ss_item, self.es_item, self.out_ann, data)
+
+ def putpw(self, data):
+ self.put(self.ss_word, self.es_word, self.out_proto, data)
+
+ def putw(self, data):
+ self.put(self.ss_word, self.es_word, self.out_ann, data)
+
+ def handle_bits(self, datapins):
+ # If this is the first item in a word, save its sample number.
+ if self.itemcount == 0:
+ self.ss_word = self.samplenum
+
+ # Get the bits for this item.
+ item, used_pins = 0, datapins.count(b'\x01') + datapins.count(b'\x00')
+ for i in range(used_pins):
+ item |= datapins[i] << i
+
+ self.items.append(item)
+ self.itemcount += 1
+
+ if self.first == True:
+ # Save the start sample and item for later (no output yet).
+ self.ss_item = self.samplenum
+ self.first = False
+ self.saved_item = item
+ else:
+ # Output the saved item (from the last CLK edge to the current).
+ self.es_item = self.samplenum
+ self.putpb(['ITEM', self.saved_item])
+ self.putb([0, ['%X' % self.saved_item]])
+ self.ss_item = self.samplenum
+ self.saved_item = item
+
+ endian, ws = self.options['endianness'], self.options['wordsize']
+
+ # Get as many items as the configured wordsize says.
+ if self.itemcount < ws:
+ return
+
+ # Output annotations/proto for a word (a collection of items).
+ word = 0
+ for i in range(ws):
+ if endian == 'little':
+ word |= self.items[i] << ((ws - 1 - i) * used_pins)
+ elif endian == 'big':
+ word |= self.items[i] << (i * used_pins)
+
+ self.es_word = self.samplenum
+ # self.putpw(['WORD', word])
+ # self.putw([1, ['%X' % word]])
+ self.ss_word = self.samplenum
+
+ self.itemcount, self.items = 0, []
+
+ def find_clk_edge(self, clk, datapins):
+ # Ignore sample if the clock pin hasn't changed.
+ if clk == self.oldclk:
+ return
+ self.oldclk = clk
+
+ # Sample data on rising/falling clock edge (depends on config).
+ c = self.options['clock_edge']
+ if c == 'rising' and clk == 0: # Sample on rising clock edge.
+ return
+ elif c == 'falling' and clk == 1: # Sample on falling clock edge.
+ return
+
+ # Found the correct clock edge, now get the bits.
+ self.handle_bits(datapins)
+
+ 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 = pins
+
+ # State machine.
+ if self.state == 'IDLE':
+ self.find_clk_edge(pins[0], pins[1:])
+ else:
+ raise Exception('Invalid state: %s' % self.state)
+
projects / libsigrokdecode.git / commitdiff