[libsigrokdecode.git] / decoders / microwire / pd.py

##
## This file is part of the libsigrokdecode project.
##
## Copyright (C) 2017 Kevin Redon <kingkevin@cuvoodoo.info>
##
## 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, see <http://www.gnu.org/licenses/>.
##

import sigrokdecode as srd
from collections import namedtuple

'''
OUTPUT_PYTHON format:

Packet:
[namedtuple('ss': bit start sample number,
  'es': bit end sample number,
  'si': SI bit,
  'so': SO bit,
 ), ...]

Since address and word size are variable, a list of all bits in each packet
need to be output. Since Microwire is a synchronous protocol with separate
input and output lines (SI and SO) they are provided together, but because
Microwire is half-duplex only the SI or SO bits will be considered at once.
To be able to annotate correctly the instructions formed by the bit, the start
and end sample number of each bit (pair of SI/SO bit) are provided.
'''

PyPacket = namedtuple('PyPacket', 'ss es si so')
Packet = namedtuple('Packet', 'samplenum matched cs sk si so')

class Decoder(srd.Decoder):
    api_version = 3
    id = 'microwire'
    name = 'Microwire'
    longname = 'Microwire'
    desc = '3-wire, half-duplex, synchronous serial bus.'
    license = 'gplv2+'
    inputs = ['logic']
    outputs = ['microwire']
    channels = (
        {'id': 'cs', 'name': 'CS', 'desc': 'Chip select'},
        {'id': 'sk', 'name': 'SK', 'desc': 'Clock'},
        {'id': 'si', 'name': 'SI', 'desc': 'Slave in'},
        {'id': 'so', 'name': 'SO', 'desc': 'Slave out'},
    )
    annotations = (
        ('start-bit', 'Start bit'),
        ('si-bit', 'SI bit'),
        ('so-bit', 'SO bit'),
        ('status-check-ready', 'Status check ready'),
        ('status-check-busy', 'Status check busy'),
        ('warning', 'Warning'),
    )
    annotation_rows = (
        ('si-bits', 'SI bits', (0, 1)),
        ('so-bits', 'SO bits', (2,)),
        ('status', 'Status', (3, 4)),
        ('warnings', 'Warnings', (5,)),
    )

    def start(self):
        self.out_python = self.register(srd.OUTPUT_PYTHON)
        self.out_ann = self.register(srd.OUTPUT_ANN)

    def decode(self):
        while True:
            # Wait for slave to be selected on rising CS.
            cs, sk, si, so = self.wait({0: 'r'})
            if sk:
                self.put(self.samplenum, self.samplenum, self.out_ann,
                     [5, ['Clock should be low on start',
                     'Clock high on start', 'Clock high', 'SK high']])
                sk = 0 # Enforce correct state for correct clock handling.
                # Because we don't know if this is bit communication or a
                # status check we have to collect the SI and SO values on SK
                # edges while the chip is selected and figure out afterwards.
            packet = []
            while cs:
                # Save change.
                packet.append(Packet(self.samplenum, self.matched, cs, sk, si, so))
                edge = 'r' if sk == 0 else 'f'
                cs, sk, si, so = self.wait([{0: 'l'}, {1: edge}, {3: 'e'}])
            # Save last change.
            packet.append(Packet(self.samplenum, self.matched, cs, sk, si, so))

            # Figure out if this is a status check.
            # Either there is no clock or no start bit (on first rising edge).
            status_check = True
            for change in packet:
                # Get first clock rising edge.
                if len(change.matched) > 1 and change.matched[1] and change.sk:
                    if change.si:
                        status_check = False
                    break

            # The packet is for a status check.
            # SO low = busy, SO high = ready.
            # The SO signal might be noisy in the beginning because it starts
            # in high impedance.
            if status_check:
                start_samplenum = packet[0].samplenum
                bit_so = packet[0].so
                # Check for SO edges.
                for change in packet:
                    if len(change.matched) > 2 and change.matched[2]:
                        if bit_so == 0 and change.so:
                            # Rising edge Busy -> Ready.
                            self.put(start_samplenum, change.samplenum,
                                     self.out_ann, [4, ['Busy', 'B']])
                        start_samplenum = change.samplenum
                        bit_so = change.so
                # Put last state.
                if bit_so == 0:
                    self.put(start_samplenum, packet[-1].samplenum,
                             self.out_ann, [4, ['Busy', 'B']])
                else:
                    self.put(start_samplenum, packet[-1].samplenum,
                             self.out_ann, [3, ['Ready', 'R']])
            else:
                # Bit communication.
                # Since the slave samples SI on clock rising edge we do the
                # same. Because the slave changes SO on clock rising edge we
                # sample on the falling edge.
                bit_start = 0 # Rising clock sample of bit start.
                bit_si = 0 # SI value at rising clock edge.
                bit_so = 0 # SO value at falling clock edge.
                start_bit = True # Start bit incoming (first bit).
                pydata = [] # Python output data.
                for change in packet:
                    if len(change.matched) > 1 and change.matched[1]:
                        # Clock edge.
                        if change.sk: # Rising clock edge.
                            if bit_start > 0: # Bit completed.
                                if start_bit:
                                    if bit_si == 0: # Start bit missing.
                                        self.put(bit_start, change.samplenum,
                                                 self.out_ann,
                                                 [5, ['Start bit not high',
                                                 'Start bit low']])
                                    else:
                                        self.put(bit_start, change.samplenum,
                                                 self.out_ann,
                                                 [0, ['Start bit', 'S']])
                                    start_bit = False
                                else:
                                    self.put(bit_start, change.samplenum,
                                             self.out_ann,
                                             [1, ['SI bit: %d' % bit_si,
                                                  'SI: %d' % bit_si,
                                                  '%d' % bit_si]])
                                    self.put(bit_start, change.samplenum,
                                             self.out_ann,
                                             [2, ['SO bit: %d' % bit_so,
                                                  'SO: %d' % bit_so,
                                                  '%d' % bit_so]])
                                    pydata.append(PyPacket(bit_start,
                                        change.samplenum, bit_si, bit_so))
                            bit_start = change.samplenum
                            bit_si = change.si
                        else: # Falling clock edge.
                            bit_so = change.so
                    elif change.matched[0] and \
                                    change.cs == 0 and change.sk == 0:
                        # End of packet.
                        self.put(bit_start, change.samplenum, self.out_ann,
                                 [1, ['SI bit: %d' % bit_si,
                                      'SI: %d' % bit_si, '%d' % bit_si]])
                        self.put(bit_start, change.samplenum, self.out_ann,
                                 [2, ['SO bit: %d' % bit_so,
                                      'SO: %d' % bit_so, '%d' % bit_so]])
                        pydata.append(PyPacket(bit_start, change.samplenum,
                                      bit_si, bit_so))
                self.put(packet[0].samplenum, packet[len(packet) - 1].samplenum,
                         self.out_python, pydata)
Commit	Line	Data
	1	##
	2	## This file is part of the libsigrokdecode project.
	3	##
	4	## Copyright (C) 2017 Kevin Redon <kingkevin@cuvoodoo.info>
	5	##
	6	## This program is free software; you can redistribute it and/or modify
	7	## it under the terms of the GNU General Public License as published by
	8	## the Free Software Foundation; either version 2 of the License, or
	9	## (at your option) any later version.
	10	##
	11	## This program is distributed in the hope that it will be useful,
	12	## but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	## GNU General Public License for more details.
	15	##
	16	## You should have received a copy of the GNU General Public License
	17	## along with this program; if not, see <http://www.gnu.org/licenses/>.
	18	##
	19
	20	import sigrokdecode as srd
	21	from collections import namedtuple
	22
	23	'''
	24	OUTPUT_PYTHON format:
	25
	26	Packet:
	27	[namedtuple('ss': bit start sample number,
	28	'es': bit end sample number,
	29	'si': SI bit,
	30	'so': SO bit,
	31	), ...]
	32
	33	Since address and word size are variable, a list of all bits in each packet
	34	need to be output. Since Microwire is a synchronous protocol with separate
	35	input and output lines (SI and SO) they are provided together, but because
	36	Microwire is half-duplex only the SI or SO bits will be considered at once.
	37	To be able to annotate correctly the instructions formed by the bit, the start
	38	and end sample number of each bit (pair of SI/SO bit) are provided.
	39	'''
	40
	41	PyPacket = namedtuple('PyPacket', 'ss es si so')
	42	Packet = namedtuple('Packet', 'samplenum matched cs sk si so')
	43
	44	class Decoder(srd.Decoder):
	45	api_version = 3
	46	id = 'microwire'
	47	name = 'Microwire'
	48	longname = 'Microwire'
	49	desc = '3-wire, half-duplex, synchronous serial bus.'
	50	license = 'gplv2+'
	51	inputs = ['logic']
	52	outputs = ['microwire']
	53	channels = (
	54	{'id': 'cs', 'name': 'CS', 'desc': 'Chip select'},
	55	{'id': 'sk', 'name': 'SK', 'desc': 'Clock'},
	56	{'id': 'si', 'name': 'SI', 'desc': 'Slave in'},
	57	{'id': 'so', 'name': 'SO', 'desc': 'Slave out'},
	58	)
	59	annotations = (
	60	('start-bit', 'Start bit'),
	61	('si-bit', 'SI bit'),
	62	('so-bit', 'SO bit'),
	63	('status-check-ready', 'Status check ready'),
	64	('status-check-busy', 'Status check busy'),
	65	('warning', 'Warning'),
	66	)
	67	annotation_rows = (
	68	('si-bits', 'SI bits', (0, 1)),
	69	('so-bits', 'SO bits', (2,)),
	70	('status', 'Status', (3, 4)),
	71	('warnings', 'Warnings', (5,)),
	72	)
	73
	74	def start(self):
	75	self.out_python = self.register(srd.OUTPUT_PYTHON)
	76	self.out_ann = self.register(srd.OUTPUT_ANN)
	77
	78	def decode(self):
	79	while True:
	80	# Wait for slave to be selected on rising CS.
	81	cs, sk, si, so = self.wait({0: 'r'})
	82	if sk:
	83	self.put(self.samplenum, self.samplenum, self.out_ann,
	84	[5, ['Clock should be low on start',
	85	'Clock high on start', 'Clock high', 'SK high']])
	86	sk = 0 # Enforce correct state for correct clock handling.
	87	# Because we don't know if this is bit communication or a
	88	# status check we have to collect the SI and SO values on SK
	89	# edges while the chip is selected and figure out afterwards.
	90	packet = []
	91	while cs:
	92	# Save change.
	93	packet.append(Packet(self.samplenum, self.matched, cs, sk, si, so))
	94	edge = 'r' if sk == 0 else 'f'
	95	cs, sk, si, so = self.wait([{0: 'l'}, {1: edge}, {3: 'e'}])
	96	# Save last change.
	97	packet.append(Packet(self.samplenum, self.matched, cs, sk, si, so))
	98
	99	# Figure out if this is a status check.
	100	# Either there is no clock or no start bit (on first rising edge).
	101	status_check = True
	102	for change in packet:
	103	# Get first clock rising edge.
	104	if len(change.matched) > 1 and change.matched[1] and change.sk:
	105	if change.si:
	106	status_check = False
	107	break
	108
	109	# The packet is for a status check.
	110	# SO low = busy, SO high = ready.
	111	# The SO signal might be noisy in the beginning because it starts
	112	# in high impedance.
	113	if status_check:
	114	start_samplenum = packet[0].samplenum
	115	bit_so = packet[0].so
	116	# Check for SO edges.
	117	for change in packet:
	118	if len(change.matched) > 2 and change.matched[2]:
	119	if bit_so == 0 and change.so:
	120	# Rising edge Busy -> Ready.
	121	self.put(start_samplenum, change.samplenum,
	122	self.out_ann, [4, ['Busy', 'B']])
	123	start_samplenum = change.samplenum
	124	bit_so = change.so
	125	# Put last state.
	126	if bit_so == 0:
	127	self.put(start_samplenum, packet[-1].samplenum,
	128	self.out_ann, [4, ['Busy', 'B']])
	129	else:
	130	self.put(start_samplenum, packet[-1].samplenum,
	131	self.out_ann, [3, ['Ready', 'R']])
	132	else:
	133	# Bit communication.
	134	# Since the slave samples SI on clock rising edge we do the
	135	# same. Because the slave changes SO on clock rising edge we
	136	# sample on the falling edge.
	137	bit_start = 0 # Rising clock sample of bit start.
	138	bit_si = 0 # SI value at rising clock edge.
	139	bit_so = 0 # SO value at falling clock edge.
	140	start_bit = True # Start bit incoming (first bit).
	141	pydata = [] # Python output data.
	142	for change in packet:
	143	if len(change.matched) > 1 and change.matched[1]:
	144	# Clock edge.
	145	if change.sk: # Rising clock edge.
	146	if bit_start > 0: # Bit completed.
	147	if start_bit:
	148	if bit_si == 0: # Start bit missing.
	149	self.put(bit_start, change.samplenum,
	150	self.out_ann,
	151	[5, ['Start bit not high',
	152	'Start bit low']])
	153	else:
	154	self.put(bit_start, change.samplenum,
	155	self.out_ann,
	156	[0, ['Start bit', 'S']])
	157	start_bit = False
	158	else:
	159	self.put(bit_start, change.samplenum,
	160	self.out_ann,
	161	[1, ['SI bit: %d' % bit_si,
	162	'SI: %d' % bit_si,
	163	'%d' % bit_si]])
	164	self.put(bit_start, change.samplenum,
	165	self.out_ann,
	166	[2, ['SO bit: %d' % bit_so,
	167	'SO: %d' % bit_so,
	168	'%d' % bit_so]])
	169	pydata.append(PyPacket(bit_start,
	170	change.samplenum, bit_si, bit_so))
	171	bit_start = change.samplenum
	172	bit_si = change.si
	173	else: # Falling clock edge.
	174	bit_so = change.so
	175	elif change.matched[0] and \
	176	change.cs == 0 and change.sk == 0:
	177	# End of packet.
	178	self.put(bit_start, change.samplenum, self.out_ann,
	179	[1, ['SI bit: %d' % bit_si,
	180	'SI: %d' % bit_si, '%d' % bit_si]])
	181	self.put(bit_start, change.samplenum, self.out_ann,
	182	[2, ['SO bit: %d' % bit_so,
	183	'SO: %d' % bit_so, '%d' % bit_so]])
	184	pydata.append(PyPacket(bit_start, change.samplenum,
	185	bit_si, bit_so))
	186	self.put(packet[0].samplenum, packet[len(packet) - 1].samplenum,
	187	self.out_python, pydata)