##
import sigrokdecode as srd
+from common.srdhelper import bitpack
from math import floor, ceil
'''
- 'INVALID STOPBIT': The data is the (integer) value of the stop bit (0/1).
- 'PARITY ERROR': The data is a tuple with two entries. The first one is
the expected parity value, the second is the actual parity value.
- - TODO: Frame error?
+ - 'BREAK': The data is always 0.
+ - 'FRAME': The data is always a tuple containing two items: The (integer)
+ value of the UART data, and a boolean which reflects the validity of the
+ UART frame.
The <rxtx> field is 0 for RX packets, 1 for TX packets.
'''
('tx-warnings', 'TX warnings'),
('rx-data-bits', 'RX data bits'),
('tx-data-bits', 'TX data bits'),
+ ('rx-break', 'RX break'),
+ ('tx-break', 'TX break'),
)
annotation_rows = (
('rx-data', 'RX', (0, 2, 4, 6, 8)),
('rx-data-bits', 'RX bits', (12,)),
('rx-warnings', 'RX warnings', (10,)),
+ ('rx-break', 'RX break', (14,)),
('tx-data', 'TX', (1, 3, 5, 7, 9)),
('tx-data-bits', 'TX bits', (13,)),
('tx-warnings', 'TX warnings', (11,)),
+ ('tx-break', 'TX break', (15,)),
)
binary = (
('rx', 'RX dump'),
s, halfbit = self.samplenum, self.bit_width / 2.0
self.put(s - floor(halfbit), s + ceil(halfbit), self.out_python, data)
+ def putgse(self, ss, es, data):
+ self.put(ss, es, self.out_ann, data)
+
+ def putpse(self, ss, es, data):
+ self.put(ss, es, self.out_python, data)
+
def putbin(self, rxtx, data):
s, halfbit = self.startsample[rxtx], self.bit_width / 2.0
self.put(s - floor(halfbit), self.samplenum + ceil(halfbit), self.out_binary, data)
def __init__(self):
+ self.reset()
+
+ def reset(self):
self.samplerate = None
self.samplenum = 0
self.frame_start = [-1, -1]
+ self.frame_valid = [None, None]
self.startbit = [-1, -1]
self.cur_data_bit = [0, 0]
self.datavalue = [0, 0]
self.startsample = [-1, -1]
self.state = ['WAIT FOR START BIT', 'WAIT FOR START BIT']
self.databits = [[], []]
+ self.break_start = [None, None]
def start(self):
self.out_python = self.register(srd.OUTPUT_PYTHON)
self.bit_width = float(self.samplerate) / float(self.options['baudrate'])
def get_sample_point(self, rxtx, bitnum):
- """Determine absolute sample number of a bit slot's sample point."""
+ # Determine absolute sample number of a bit slot's sample point.
# bitpos is the samplenumber which is in the middle of the
# specified UART bit (0 = start bit, 1..x = data, x+1 = parity bit
# (if used) or the first stop bit, and so on).
bitpos += bitnum * self.bit_width
return bitpos
- # Return true if we reached the middle of the desired bit, false otherwise.
- def reached_bit(self, rxtx, bitnum):
- bitpos = self.get_sample_point(rxtx, bitnum)
- if self.samplenum >= bitpos:
- return True
- return False
-
def wait_for_start_bit(self, rxtx, signal):
- # The caller already has detected an edge. Strictly speaking this
- # check on the current signal level is redundant. But it does not
- # harm either.
- if signal != 0:
- return
-
# Save the sample number where the start bit begins.
self.frame_start[rxtx] = self.samplenum
+ self.frame_valid[rxtx] = True
self.state[rxtx] = 'GET START BIT'
def get_start_bit(self, rxtx, signal):
- # Skip samples until we're in the middle of the start bit.
- if not self.reached_bit(rxtx, 0):
- return
-
self.startbit[rxtx] = signal
# The startbit must be 0. If not, we report an error and wait
if self.startbit[rxtx] != 0:
self.putp(['INVALID STARTBIT', rxtx, self.startbit[rxtx]])
self.putg([rxtx + 10, ['Frame error', 'Frame err', 'FE']])
+ self.frame_valid[rxtx] = False
+ es = self.samplenum + ceil(self.bit_width / 2.0)
+ self.putpse(self.frame_start[rxtx], es, ['FRAME', rxtx,
+ (self.datavalue[rxtx], self.frame_valid[rxtx])])
self.state[rxtx] = 'WAIT FOR START BIT'
return
self.datavalue[rxtx] = 0
self.startsample[rxtx] = -1
- self.state[rxtx] = 'GET DATA BITS'
-
self.putp(['STARTBIT', rxtx, self.startbit[rxtx]])
self.putg([rxtx + 2, ['Start bit', 'Start', 'S']])
- def get_data_bits(self, rxtx, signal):
- # Skip samples until we're in the middle of the desired data bit.
- if not self.reached_bit(rxtx, 1 + self.cur_data_bit[rxtx]):
- return
+ self.state[rxtx] = 'GET DATA BITS'
+ def get_data_bits(self, rxtx, signal):
# Save the sample number of the middle of the first data bit.
if self.startsample[rxtx] == -1:
self.startsample[rxtx] = self.samplenum
- # Get the next data bit in LSB-first or MSB-first fashion.
- if self.options['bit_order'] == 'lsb-first':
- self.datavalue[rxtx] >>= 1
- self.datavalue[rxtx] |= \
- (signal << (self.options['num_data_bits'] - 1))
- else:
- self.datavalue[rxtx] <<= 1
- self.datavalue[rxtx] |= (signal << 0)
-
self.putg([rxtx + 12, ['%d' % signal]])
# Store individual data bits and their start/end samplenumbers.
if self.cur_data_bit[rxtx] < self.options['num_data_bits']:
return
- # Skip to either reception of the parity bit, or reception of
- # the STOP bits if parity is not applicable.
- self.state[rxtx] = 'GET PARITY BIT'
- if self.options['parity_type'] == 'none':
- self.state[rxtx] = 'GET STOP BITS'
-
+ # Convert accumulated data bits to a data value.
+ bits = [b[0] for b in self.databits[rxtx]]
+ if self.options['bit_order'] == 'msb-first':
+ bits.reverse()
+ self.datavalue[rxtx] = bitpack(bits)
self.putpx(rxtx, ['DATA', rxtx,
(self.datavalue[rxtx], self.databits[rxtx])])
self.databits[rxtx] = []
+ # Advance to either reception of the parity bit, or reception of
+ # the STOP bits if parity is not applicable.
+ self.state[rxtx] = 'GET PARITY BIT'
+ if self.options['parity_type'] == 'none':
+ self.state[rxtx] = 'GET STOP BITS'
+
def format_value(self, v):
# Format value 'v' according to configured options.
# Reflects the user selected kind of representation, as well as
return None
def get_parity_bit(self, rxtx, signal):
- # Skip samples until we're in the middle of the parity bit.
- if not self.reached_bit(rxtx, 1 + self.options['num_data_bits']):
- return
-
self.paritybit[rxtx] = signal
- self.state[rxtx] = 'GET STOP BITS'
-
if parity_ok(self.options['parity_type'], self.paritybit[rxtx],
self.datavalue[rxtx], self.options['num_data_bits']):
self.putp(['PARITYBIT', rxtx, self.paritybit[rxtx]])
# TODO: Return expected/actual parity values.
self.putp(['PARITY ERROR', rxtx, (0, 1)]) # FIXME: Dummy tuple...
self.putg([rxtx + 6, ['Parity error', 'Parity err', 'PE']])
+ self.frame_valid[rxtx] = False
+
+ self.state[rxtx] = 'GET STOP BITS'
# TODO: Currently only supports 1 stop bit.
def get_stop_bits(self, rxtx, signal):
- # Skip samples until we're in the middle of the stop bit(s).
- skip_parity = 0 if self.options['parity_type'] == 'none' else 1
- b = 1 + self.options['num_data_bits'] + skip_parity
- if not self.reached_bit(rxtx, b):
- return
-
self.stopbit1[rxtx] = signal
# Stop bits must be 1. If not, we report an error.
if self.stopbit1[rxtx] != 1:
self.putp(['INVALID STOPBIT', rxtx, self.stopbit1[rxtx]])
self.putg([rxtx + 10, ['Frame error', 'Frame err', 'FE']])
- # TODO: Abort? Ignore the frame? Other?
-
- self.state[rxtx] = 'WAIT FOR START BIT'
+ self.frame_valid[rxtx] = False
self.putp(['STOPBIT', rxtx, self.stopbit1[rxtx]])
self.putg([rxtx + 4, ['Stop bit', 'Stop', 'T']])
- def get_wait_cond(self, rxtx, inv):
- """
- Determine Decoder.wait() condition for specified UART line.
+ # Pass the complete UART frame to upper layers.
+ es = self.samplenum + ceil(self.bit_width / 2.0)
+ self.putpse(self.frame_start[rxtx], es, ['FRAME', rxtx,
+ (self.datavalue[rxtx], self.frame_valid[rxtx])])
- Returns condititions that are suitable for Decoder.wait(). Those
- conditions either match the falling edge of the START bit, or
- the sample point of the next bit time.
- """
+ self.state[rxtx] = 'WAIT FOR START BIT'
+
+ def handle_break(self, rxtx):
+ self.putpse(self.frame_start[rxtx], self.samplenum,
+ ['BREAK', rxtx, 0])
+ self.putgse(self.frame_start[rxtx], self.samplenum,
+ [rxtx + 14, ['Break condition', 'Break', 'Brk', 'B']])
+ self.state[rxtx] = 'WAIT FOR START BIT'
+ def get_wait_cond(self, rxtx, inv):
+ # Return condititions that are suitable for Decoder.wait(). Those
+ # conditions either match the falling edge of the START bit, or
+ # the sample point of the next bit time.
state = self.state[rxtx]
if state == 'WAIT FOR START BIT':
return {rxtx: 'r' if inv else 'f'}
elif state == 'GET STOP BITS':
bitnum = 1 + self.options['num_data_bits']
bitnum += 0 if self.options['parity_type'] == 'none' else 1
- want_num = self.get_sample_point(rxtx, bitnum)
- # want_num = int(want_num + 0.5)
- want_num = ceil(want_num)
- cond = {'skip': want_num - self.samplenum}
- return cond
+ want_num = ceil(self.get_sample_point(rxtx, bitnum))
+ return {'skip': want_num - self.samplenum}
def inspect_sample(self, rxtx, signal, inv):
- """Inspect a sample returned by .wait() for the specified UART line."""
-
+ # Inspect a sample returned by .wait() for the specified UART line.
if inv:
signal = not signal
elif state == 'GET STOP BITS':
self.get_stop_bits(rxtx, signal)
+ def inspect_edge(self, rxtx, signal, inv):
+ # Inspect edges, independently from traffic, to detect break conditions.
+ if inv:
+ signal = not signal
+ if not signal:
+ # Signal went low. Start another interval.
+ self.break_start[rxtx] = self.samplenum
+ return
+ # Signal went high. Was there an extended period with low signal?
+ if self.break_start[rxtx] is None:
+ return
+ diff = self.samplenum - self.break_start[rxtx]
+ if diff >= self.break_min_sample_count:
+ self.handle_break(rxtx)
+ self.break_start[rxtx] = None
+
def decode(self):
if not self.samplerate:
raise SamplerateError('Cannot decode without samplerate.')
opt = self.options
inv = [opt['invert_rx'] == 'yes', opt['invert_tx'] == 'yes']
+ cond_data_idx = [None] * len(has_pin)
+
+ # Determine the number of samples for a complete frame's time span.
+ # A period of low signal (at least) that long is a break condition.
+ frame_samples = 1 # START
+ frame_samples += self.options['num_data_bits']
+ frame_samples += 0 if self.options['parity_type'] == 'none' else 1
+ frame_samples += self.options['num_stop_bits']
+ frame_samples *= self.bit_width
+ self.break_min_sample_count = ceil(frame_samples)
+ cond_edge_idx = [None] * len(has_pin)
while True:
conds = []
if has_pin[RX]:
+ cond_data_idx[RX] = len(conds)
conds.append(self.get_wait_cond(RX, inv[RX]))
+ cond_edge_idx[RX] = len(conds)
+ conds.append({RX: 'e'})
if has_pin[TX]:
+ cond_data_idx[TX] = len(conds)
conds.append(self.get_wait_cond(TX, inv[TX]))
+ cond_edge_idx[TX] = len(conds)
+ conds.append({TX: 'e'})
(rx, tx) = self.wait(conds)
- if has_pin[RX]:
+ if cond_data_idx[RX] is not None and self.matched[cond_data_idx[RX]]:
self.inspect_sample(RX, rx, inv[RX])
- if has_pin[TX]:
+ if cond_edge_idx[RX] is not None and self.matched[cond_edge_idx[RX]]:
+ self.inspect_edge(RX, rx, inv[RX])
+ if cond_data_idx[TX] is not None and self.matched[cond_data_idx[TX]]:
self.inspect_sample(TX, tx, inv[TX])
+ if cond_edge_idx[TX] is not None and self.matched[cond_edge_idx[TX]]:
+ self.inspect_edge(TX, tx, inv[TX])
projects / libsigrokdecode.git / blobdiff