##
## This file is part of the libsigrokdecode project.
##
## Copyright (C) 2020 Soeren Apel <soeren@apelpie.net>
##
## 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 common.srdhelper import bitpack
import decimal
'''
OUTPUT_PYTHON format:
[ss, es, data] where data is a data byte of the LFAST payload. All bytes of
the payload are sent at once, each with its start and end sample.
'''
# See tc27xD_um_v2.2.pdf, Table 20-10
payload_sizes = {
0b000: '8 bit',
0b001: '32 bit / 4 byte',
0b010: '64 bit / 8 byte',
0b011: '96 bit / 12 byte',
0b100: '128 bit / 16 byte',
0b101: '256 bit / 32 byte',
0b110: '512 bit / 64 byte',
0b111: '288 bit / 36 byte'
}
# See tc27xD_um_v2.2.pdf, Table 20-10
payload_byte_sizes = {
0b000: 1,
0b001: 4,
0b010: 8,
0b011: 12,
0b100: 16,
0b101: 32,
0b110: 64,
0b111: 36
}
# See tc27xD_um_v2.2.pdf, Table 20-11
channel_types = {
0b0000: 'Interface Control / PING',
0b0001: 'Unsolicited Status (32 bit)',
0b0010: 'Slave Interface Control / Read',
0b0011: 'CTS Transfer',
0b0100: 'Data Channel A',
0b0101: 'Data Channel B',
0b0110: 'Data Channel C',
0b0111: 'Data Channel D',
0b1000: 'Data Channel E',
0b1001: 'Data Channel F',
0b1010: 'Data Channel G',
0b1011: 'Data Channel H',
0b1100: 'Reserved',
0b1101: 'Reserved',
0b1110: 'Reserved',
0b1111: 'Reserved',
}
# See tc27xD_um_v2.2.pdf, Table 20-12
control_payloads = {
0x00: 'PING',
0x01: 'Reserved',
0x02: 'Slave interface clock multiplier start',
0x04: 'Slave interface clock multiplier stop',
0x08: 'Use 5 MBaud for M->S',
0x10: 'Use 320 MBaud for M->S',
0x20: 'Use 5 MBaud for S->M',
0x40: 'Use 20 MBaud for S->M (needs 20 MHz SysClk)',
0x80: 'Use 320 MBaud for S->M',
0x31: 'Enable slave interface transmitter',
0x32: 'Disable slave interface transmitter',
0x34: 'Enable clock test mode',
0x38: 'Disable clock test mode and payload loopback',
0xFF: 'Enable payload loopback',
}
ann_bit, ann_sync, ann_header_pl_size, ann_header_ch_type, ann_header_cts, \
ann_payload, ann_control_data, ann_sleepbit, ann_warning = range(9)
state_sync, state_header, state_payload, state_sleepbit = range(4)
class Decoder(srd.Decoder):
api_version = 3
id = 'lfast'
name = 'LFAST'
longname = 'NXP LFAST interface'
desc = 'Differential high-speed P2P interface'
license = 'gplv2+'
inputs = ['logic']
outputs = ['lfast']
tags = ['Embedded/industrial']
channels = (
{'id': 'data', 'name': 'Data', 'desc': 'TXP or RXP'},
)
annotations = (
('bit', 'Bits'),
('sync', 'Sync Pattern'),
('header_pl_size', 'Payload Size'),
('header_ch_type', 'Logical Channel Type'),
('header_cts', 'Clear To Send'),
('payload', 'Payload'),
('ctrl_data', 'Control Data'),
('sleep', 'Sleep Bit'),
('warning', 'Warning'),
)
annotation_rows = (
('bits', 'Bits', (ann_bit,)),
('fields', 'Fields', (ann_sync, ann_header_pl_size, ann_header_ch_type,
ann_header_cts, ann_payload, ann_control_data, ann_sleepbit,)),
('warnings', 'Warnings', (ann_warning,)),
)
def __init__(self):
decimal.getcontext().rounding = decimal.ROUND_HALF_UP
self.bit_len = 0xFFFFFFFF
self.reset()
def reset(self):
self.prev_bit_len = self.bit_len
self.ss = self.es = 0
self.ss_payload = self.es_payload = 0
self.ss_byte = 0
self.bits = []
self.payload = []
self.payload_size = 0 # Expected number of bytes, as read from header
self.bit_len = 0 # Length of one bit time, in samples
self.timeout = 0 # Desired timeout for next edge, in samples
self.ch_type_id = 0 # ID of channel type
self.state = state_sync
def metadata(self, key, value):
pass
def start(self):
self.out_python = self.register(srd.OUTPUT_PYTHON)
self.out_ann = self.register(srd.OUTPUT_ANN)
def put_ann(self, ss, es, ann_class, value):
self.put(ss, es, self.out_ann, [ann_class, value])
def put_payload(self):
self.put(self.ss_payload, self.es_payload, self.out_python, self.payload)
def handle_sync(self):
if len(self.bits) == 1:
self.ss_sync = self.ss_bit
if len(self.bits) == 16:
value = bitpack(self.bits)
if value == 0xA84B:
self.put_ann(self.ss_sync, self.es_bit, ann_sync, ['Sync OK'])
else:
self.put_ann(self.ss_sync, self.es_bit, ann_warning, ['Wrong Sync Value: {:02X}'.format(value)])
self.reset()
# Only continue if we didn't just reset
if self.ss > 0:
self.bits = []
self.state = state_header
self.timeout = int(9.4 * self.bit_len)
def handle_header(self):
if len(self.bits) == 1:
self.ss_header = self.ss_bit
if len(self.bits) == 8:
# See tc27xD_um_v2.2.pdf, Figure 20-47, for the header structure
bit_len = (self.es_bit - self.ss_header) / 8
value = bitpack(self.bits)
ss = self.ss_header
es = ss + 3 * bit_len
size_id = (value & 0xE0) >> 5
size = payload_sizes.get(size_id)
self.payload_size = payload_byte_sizes.get(size_id)
self.put_ann(int(ss), int(es), ann_header_pl_size, [size])
ss = es
es = ss + 4 * bit_len
self.ch_type_id = (value & 0x1E) >> 1
ch_type = channel_types.get(self.ch_type_id)
self.put_ann(int(ss), int(es), ann_header_ch_type, [ch_type])
ss = es
es = ss + bit_len
cts = value & 0x01
self.put_ann(int(ss), int(es), ann_header_cts, ['{}'.format(cts)])
self.bits = []
self.state = state_payload
self.timeout = int(9.4 * self.bit_len)
def handle_payload(self):
self.timeout = int((self.payload_size - len(self.payload)) * 8 * self.bit_len)
if len(self.bits) == 1:
self.ss_byte = self.ss_bit
if self.ss_payload == 0:
self.ss_payload = self.ss_bit
if len(self.bits) == 8:
value = bitpack(self.bits)
value_hex = '{:02X}'.format(value)
# Control transfers have no SIPI payload, show them as control transfers
# Check the channel_types list for the meaning of the magic values
if (self.ch_type_id >= 0b0100) and (self.ch_type_id <= 0b1011):
self.put_ann(self.ss_byte, self.es_bit, ann_payload, [value_hex])
else:
# Control transfers are 8-bit transfers, so only evaluate the first byte
if len(self.payload) == 0:
ctrl_data = control_payloads.get(value, value_hex)
self.put_ann(self.ss_byte, self.es_bit, ann_control_data, [ctrl_data])
else:
self.put_ann(self.ss_byte, self.es_bit, ann_control_data, [value_hex])
self.bits = []
self.es_payload = self.es_bit
self.payload.append((self.ss_byte, self.es_payload, value))
if (len(self.payload) == self.payload_size):
self.timeout = int(1.4 * self.bit_len)
self.state = state_sleepbit
def handle_sleepbit(self):
if len(self.bits) == 0:
self.put_ann(self.ss_bit, self.es_bit, ann_sleepbit, ['No LVDS sleep mode request', 'No sleep', 'N'])
elif len(self.bits) > 1:
self.put_ann(self.ss_bit, self.es_bit, ann_warning, ['Expected only the sleep bit, got {} bits instead'.format(len(self.bits))])
else:
if self.bits[0] == 1:
self.put_ann(self.ss_bit, self.es_bit, ann_sleepbit, ['LVDS sleep mode request', 'Sleep', 'Y'])
else:
self.put_ann(self.ss_bit, self.es_bit, ann_sleepbit, ['No LVDS sleep mode request', 'No sleep', 'N'])
# We only send the payload out if this is an actual data transfer;
# check the channel_types list for the meaning of the magic values
if (self.ch_type_id >= 0b0100) and (self.ch_type_id <= 0b1011):
if len(self.payload) > 0:
self.put_payload()
def decode(self):
while True:
if self.timeout == 0:
rising_edge, = self.wait({0: 'e'})
else:
rising_edge, = self.wait([{0: 'e'}, {'skip': self.timeout}])
# If this is the first edge, we only update ss
if self.ss == 0:
self.ss = self.samplenum
# Let's set the timeout for the sync pattern as well
self.timeout = int(16.2 * self.prev_bit_len)
continue
self.es = self.samplenum
# Check for the sleep bit if this is a timeout condition
if (len(self.matched) == 2) and self.matched[1]:
rising_edge = ~rising_edge
if self.state == state_sync:
self.reset()
continue
elif self.state == state_sleepbit:
self.ss_bit += self.bit_len
self.es_bit = self.ss_bit + self.bit_len
self.handle_sleepbit()
self.reset()
continue
# Shouldn't happen but we check just in case
if int(self.es - self.ss) == 0:
continue
# We use the first bit to deduce the bit length
if self.bit_len == 0:
self.bit_len = self.es - self.ss
# Determine number of bits covered by this edge
bit_count = (self.es - self.ss) / self.bit_len
bit_count = int(decimal.Decimal(bit_count).to_integral_value())
if bit_count == 0:
self.put_ann(self.ss, self.es, ann_warning, ['Bit time too short'])
self.reset()
continue
bit_value = '0' if rising_edge else '1'
divided_len = (self.es - self.ss) / bit_count
for i in range(bit_count):
self.ss_bit = int(self.ss + i * divided_len)
self.es_bit = int(self.ss_bit + divided_len)
self.put_ann(self.ss_bit, self.es_bit, ann_bit, [bit_value])
# Place the new bit at the front of the bit list
self.bits.insert(0, (0 if rising_edge else 1))
if self.state == state_sync:
self.handle_sync()
elif self.state == state_header:
self.handle_header()
elif self.state == state_payload:
self.handle_payload()
elif self.state == state_sleepbit:
self.handle_sleepbit()
self.reset()
if self.ss == 0:
break # Because reset() was called, invalidating everything
# Only update ss if we didn't just perform a reset
if self.ss > 0:
self.ss = self.samplenum
# If we got here when a timeout occurred, we have processed all null
# bits that we could and should reset now to find the next packet
if (len(self.matched) == 2) and self.matched[1]:
self.reset()