[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
bf014116 KR	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
15c107c2	21	from collections import namedtuple
bf014116 KR	22
	23	'''
	24	OUTPUT_PYTHON format:
	25
	26	Packet:
15c107c2	27	[namedtuple('ss': bit start sample number,
5f914c47	28	'es': bit end sample number,
bf014116 KR	29	'si': SI bit,
bf014116 KR	30	'so': SO bit,
15c107c2	31	), ...]
bf014116	32
fe9e9ceb	33	Since address and word size are variable, a list of all bits in each packet
bf014116 KR	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
5f914c47	41	PyPacket = namedtuple('PyPacket', 'ss es si so')
9fb04bdf	42	Packet = namedtuple('Packet', 'samplenum matched cs sk si so')
15c107c2	43
bf014116 KR	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 = (
bf3d8c80	60	('start-bit', 'Start bit'),
bf014116 KR	61	('si-bit', 'SI bit'),
bf014116 KR	62	('so-bit', 'SO bit'),
0e081655 UH	63	('status-check-ready', 'Status check ready'),
0e081655 UH	64	('status-check-busy', 'Status check busy'),
bf014116 KR	65	('warning', 'Warning'),
	66	)
	67	annotation_rows = (
bf3d8c80 UH	68	('si-bits', 'SI bits', (0, 1)),
bf3d8c80 UH	69	('so-bits', 'SO bits', (2,)),
0e081655 UH	70	('status', 'Status', (3, 4)),
0e081655 UH	71	('warnings', 'Warnings', (5,)),
bf014116 KR	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,
0e081655	84	[5, ['Clock should be low on start',
bf014116 KR	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.
9fb04bdf	93	packet.append(Packet(self.samplenum, self.matched, cs, sk, si, so))
13c484dd UH	94	edge = 'r' if sk == 0 else 'f'
13c484dd UH	95	cs, sk, si, so = self.wait([{0: 'l'}, {1: edge}, {3: 'e'}])
bf014116	96	# Save last change.
9fb04bdf	97	packet.append(Packet(self.samplenum, self.matched, cs, sk, si, so))
bf014116 KR	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.
9fb04bdf UH	104	if len(change.matched) > 1 and change.matched[1] and change.sk:
9fb04bdf UH	105	if change.si:
bf014116 KR	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:
9fb04bdf UH	114	start_samplenum = packet[0].samplenum
9fb04bdf UH	115	bit_so = packet[0].so
bf014116 KR	116	# Check for SO edges.
bf014116 KR	117	for change in packet:
9fb04bdf UH	118	if len(change.matched) > 2 and change.matched[2]:
9fb04bdf UH	119	if bit_so == 0 and change.so:
bf014116	120	# Rising edge Busy -> Ready.
9fb04bdf	121	self.put(start_samplenum, change.samplenum,
0e081655	122	self.out_ann, [4, ['Busy', 'B']])
9fb04bdf UH	123	start_samplenum = change.samplenum
9fb04bdf UH	124	bit_so = change.so
bf014116 KR	125	# Put last state.
bf014116 KR	126	if bit_so == 0:
9fb04bdf	127	self.put(start_samplenum, packet[-1].samplenum,
0e081655	128	self.out_ann, [4, ['Busy', 'B']])
bf014116	129	else:
9fb04bdf	130	self.put(start_samplenum, packet[-1].samplenum,
bf3d8c80	131	self.out_ann, [3, ['Ready', 'R']])
bf014116 KR	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).
15c107c2	141	pydata = [] # Python output data.
bf014116	142	for change in packet:
9fb04bdf	143	if len(change.matched) > 1 and change.matched[1]:
bf014116	144	# Clock edge.
9fb04bdf	145	if change.sk: # Rising clock edge.
bf014116 KR	146	if bit_start > 0: # Bit completed.
	147	if start_bit:
	148	if bit_si == 0: # Start bit missing.
9fb04bdf	149	self.put(bit_start, change.samplenum,
bf014116	150	self.out_ann,
0e081655	151	[5, ['Start bit not high',
bf014116 KR	152	'Start bit low']])
bf014116 KR	153	else:
9fb04bdf	154	self.put(bit_start, change.samplenum,
bf014116 KR	155	self.out_ann,
	156	[0, ['Start bit', 'S']])
	157	start_bit = False
	158	else:
9fb04bdf	159	self.put(bit_start, change.samplenum,
bf014116	160	self.out_ann,
bf3d8c80	161	[1, ['SI bit: %d' % bit_si,
bf014116 KR	162	'SI: %d' % bit_si,
bf014116 KR	163	'%d' % bit_si]])
9fb04bdf	164	self.put(bit_start, change.samplenum,
bf014116	165	self.out_ann,
bf3d8c80	166	[2, ['SO bit: %d' % bit_so,
bf014116 KR	167	'SO: %d' % bit_so,
bf014116 KR	168	'%d' % bit_so]])
15c107c2	169	pydata.append(PyPacket(bit_start,
9fb04bdf UH	170	change.samplenum, bit_si, bit_so))
	171	bit_start = change.samplenum
	172	bit_si = change.si
bf014116	173	else: # Falling clock edge.
9fb04bdf UH	174	bit_so = change.so
	175	elif change.matched[0] and \
	176	change.cs == 0 and change.sk == 0:
bf014116	177	# End of packet.
9fb04bdf	178	self.put(bit_start, change.samplenum, self.out_ann,
bf3d8c80	179	[1, ['SI bit: %d' % bit_si,
bf014116	180	'SI: %d' % bit_si, '%d' % bit_si]])
9fb04bdf	181	self.put(bit_start, change.samplenum, self.out_ann,
bf3d8c80	182	[2, ['SO bit: %d' % bit_so,
bf014116	183	'SO: %d' % bit_so, '%d' % bit_so]])
9fb04bdf	184	pydata.append(PyPacket(bit_start, change.samplenum,
15c107c2	185	bit_si, bit_so))
9fb04bdf	186	self.put(packet[0].samplenum, packet[len(packet) - 1].samplenum,
15c107c2	187	self.out_python, pydata)