##
import sigrokdecode as srd
+from common.srdhelper import bitpack
from math import floor, ceil
'''
pass
class Decoder(srd.Decoder):
- api_version = 2
+ api_version = 3
id = 'uart'
name = 'UART'
longname = 'Universal Asynchronous Receiver/Transmitter'
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.stopbit1 = [-1, -1]
self.startsample = [-1, -1]
self.state = ['WAIT FOR START BIT', 'WAIT FOR START BIT']
- self.oldbit = [1, 1]
- self.oldpins = [-1, -1]
self.databits = [[], []]
def start(self):
# The width of one UART bit in number of samples.
self.bit_width = float(self.samplerate) / float(self.options['baudrate'])
- # Return true if we reached the middle of the desired bit, false otherwise.
- def reached_bit(self, rxtx, bitnum):
+ def get_sample_point(self, rxtx, bitnum):
+ # 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).
# index of the middle sample within bit window is (bit_width - 1) / 2.
bitpos = self.frame_start[rxtx] + (self.bit_width - 1) / 2.0
bitpos += bitnum * self.bit_width
- if self.samplenum >= bitpos:
- return True
- return False
-
- def wait_for_start_bit(self, rxtx, old_signal, signal):
- # The start bit is always 0 (low). As the idle UART (and the stop bit)
- # level is 1 (high), the beginning of a start bit is a falling edge.
- if not (old_signal == 1 and signal == 0):
- return
+ return bitpos
+ def wait_for_start_bit(self, rxtx, signal):
# Save the sample number where the start bit begins.
self.frame_start[rxtx] = self.samplenum
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
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]])
self.putp(['PARITY ERROR', rxtx, (0, 1)]) # FIXME: Dummy tuple...
self.putg([rxtx + 6, ['Parity error', 'Parity err', 'PE']])
+ 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.
self.putg([rxtx + 10, ['Frame error', 'Frame err', 'FE']])
# TODO: Abort? Ignore the frame? Other?
- self.state[rxtx] = 'WAIT FOR START BIT'
-
self.putp(['STOPBIT', rxtx, self.stopbit1[rxtx]])
self.putg([rxtx + 4, ['Stop bit', 'Stop', 'T']])
- def decode(self, ss, es, data):
+ 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'}
+ if state == 'GET START BIT':
+ bitnum = 0
+ elif state == 'GET DATA BITS':
+ bitnum = 1 + self.cur_data_bit[rxtx]
+ elif state == 'GET PARITY BIT':
+ bitnum = 1 + self.options['num_data_bits']
+ elif state == 'GET STOP BITS':
+ bitnum = 1 + self.options['num_data_bits']
+ bitnum += 0 if self.options['parity_type'] == 'none' else 1
+ 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.
+ if inv:
+ signal = not signal
+
+ state = self.state[rxtx]
+ if state == 'WAIT FOR START BIT':
+ self.wait_for_start_bit(rxtx, signal)
+ elif state == 'GET START BIT':
+ self.get_start_bit(rxtx, signal)
+ elif state == 'GET DATA BITS':
+ self.get_data_bits(rxtx, signal)
+ elif state == 'GET PARITY BIT':
+ self.get_parity_bit(rxtx, signal)
+ elif state == 'GET STOP BITS':
+ self.get_stop_bits(rxtx, signal)
+
+ def decode(self):
if not self.samplerate:
raise SamplerateError('Cannot decode without samplerate.')
- for (self.samplenum, pins) in data:
-
- # We want to skip identical samples for performance reasons but,
- # for now, we can only do that when we are in the idle state
- # (meaning both channels are waiting for the start bit).
- if self.state == self.idle_state and self.oldpins == pins:
- continue
-
- self.oldpins, (rx, tx) = pins, pins
-
- if self.options['invert_rx'] == 'yes':
- rx = not rx
- if self.options['invert_tx'] == 'yes':
- tx = not tx
-
- # Either RX or TX (but not both) can be omitted.
- has_pin = [rx in (0, 1), tx in (0, 1)]
- if has_pin == [False, False]:
- raise ChannelError('Either TX or RX (or both) pins required.')
-
- # State machine.
- for rxtx in (RX, TX):
- # Don't try to handle RX (or TX) if not supplied.
- if not has_pin[rxtx]:
- continue
-
- signal = rx if (rxtx == RX) else tx
-
- if self.state[rxtx] == 'WAIT FOR START BIT':
- self.wait_for_start_bit(rxtx, self.oldbit[rxtx], signal)
- elif self.state[rxtx] == 'GET START BIT':
- self.get_start_bit(rxtx, signal)
- elif self.state[rxtx] == 'GET DATA BITS':
- self.get_data_bits(rxtx, signal)
- elif self.state[rxtx] == 'GET PARITY BIT':
- self.get_parity_bit(rxtx, signal)
- elif self.state[rxtx] == 'GET STOP BITS':
- self.get_stop_bits(rxtx, signal)
-
- # Save current RX/TX values for the next round.
- self.oldbit[rxtx] = signal
+
+ has_pin = [self.has_channel(ch) for ch in (RX, TX)]
+ if has_pin == [False, False]:
+ raise ChannelError('Either TX or RX (or both) pins required.')
+
+ opt = self.options
+ inv = [opt['invert_rx'] == 'yes', opt['invert_tx'] == 'yes']
+ cond_idx = [None] * len(has_pin)
+
+ while True:
+ conds = []
+ if has_pin[RX]:
+ cond_idx[RX] = len(conds)
+ conds.append(self.get_wait_cond(RX, inv[RX]))
+ if has_pin[TX]:
+ cond_idx[TX] = len(conds)
+ conds.append(self.get_wait_cond(TX, inv[TX]))
+ (rx, tx) = self.wait(conds)
+ if cond_idx[RX] is not None and self.matched[cond_idx[RX]]:
+ self.inspect_sample(RX, rx, inv[RX])
+ if cond_idx[TX] is not None and self.matched[cond_idx[TX]]:
+ self.inspect_sample(TX, tx, inv[TX])
projects / libsigrokdecode.git / blobdiff