## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
##
-#
# UART protocol decoder
-#
import sigrokdecode as srd
-# States
-WAIT_FOR_START_BIT = 0
-GET_START_BIT = 1
-GET_DATA_BITS = 2
-GET_PARITY_BIT = 3
-GET_STOP_BITS = 4
-
# Used for differentiating between the two data directions.
RX = 0
TX = 1
-# Parity options
-PARITY_NONE = 0
-PARITY_ODD = 1
-PARITY_EVEN = 2
-PARITY_ZERO = 3
-PARITY_ONE = 4
-
-# Stop bit options
-STOP_BITS_0_5 = 0
-STOP_BITS_1 = 1
-STOP_BITS_1_5 = 2
-STOP_BITS_2 = 3
-
-# Bit order options
-LSB_FIRST = 0
-MSB_FIRST = 1
-
# Annotation feed formats
ANN_ASCII = 0
ANN_DEC = 1
# Given a parity type to check (odd, even, zero, one), the value of the
# parity bit, the value of the data, and the length of the data (5-9 bits,
# usually 8 bits) return True if the parity is correct, False otherwise.
-# PARITY_NONE is _not_ allowed as value for 'parity_type'.
+# 'none' is _not_ allowed as value for 'parity_type'.
def parity_ok(parity_type, parity_bit, data, num_data_bits):
# Handle easy cases first (parity bit is always 1 or 0).
- if parity_type == PARITY_ZERO:
+ if parity_type == 'zero':
return parity_bit == 0
- elif parity_type == PARITY_ONE:
+ elif parity_type == 'one':
return parity_bit == 1
# Count number of 1 (high) bits in the data (and the parity bit itself!).
ones = bin(data).count('1') + parity_bit
# Check for odd/even parity.
- if parity_type == PARITY_ODD:
+ if parity_type == 'odd':
return (ones % 2) == 1
- elif parity_type == PARITY_EVEN:
+ elif parity_type == 'even':
return (ones % 2) == 0
else:
raise Exception('Invalid parity type: %d' % parity_type)
id = 'uart'
name = 'UART'
longname = 'Universal Asynchronous Receiver/Transmitter'
- desc = 'Universal Asynchronous Receiver/Transmitter (UART)'
- longdesc = 'TODO.'
+ desc = 'Asynchronous, serial bus.'
license = 'gplv2+'
inputs = ['logic']
outputs = ['uart']
options = {
'baudrate': ['Baud rate', 115200],
'num_data_bits': ['Data bits', 8], # Valid: 5-9.
- 'parity_type': ['Parity type', PARITY_NONE],
- 'parity_check': ['Check parity?', True], # TODO: Bool supported?
- 'num_stop_bits': ['Stop bit(s)', STOP_BITS_1],
- 'bit_order': ['Bit order', LSB_FIRST],
+ 'parity_type': ['Parity type', 'none'],
+ 'parity_check': ['Check parity?', 'yes'], # TODO: Bool supported?
+ 'num_stop_bits': ['Stop bit(s)', '1'], # String! 0, 0.5, 1, 1.5.
+ 'bit_order': ['Bit order', 'lsb-first'],
# TODO: Options to invert the signal(s).
}
annotations = [
self.paritybit = [-1, -1]
self.stopbit1 = [-1, -1]
self.startsample = [-1, -1]
-
- # Initial state.
- self.state = [WAIT_FOR_START_BIT, WAIT_FOR_START_BIT]
-
+ self.state = ['WAIT FOR START BIT', 'WAIT FOR START BIT']
self.oldbit = [None, None]
+ self.oldpins = None
def start(self, metadata):
self.samplerate = metadata['samplerate']
# Save the sample number where the start bit begins.
self.frame_start[rxtx] = self.samplenum
- self.state[rxtx] = GET_START_BIT
+ 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.
self.databyte[rxtx] = 0
self.startsample[rxtx] = -1
- self.state[rxtx] = GET_DATA_BITS
+ self.state[rxtx] = 'GET DATA BITS'
self.put(self.frame_start[rxtx], self.samplenum, self.out_proto,
['STARTBIT', rxtx, self.startbit[rxtx]])
self.startsample[rxtx] = self.samplenum
# Get the next data bit in LSB-first or MSB-first fashion.
- if self.options['bit_order'] == LSB_FIRST:
+ if self.options['bit_order'] == 'lsb-first':
self.databyte[rxtx] >>= 1
self.databyte[rxtx] |= \
(signal << (self.options['num_data_bits'] - 1))
- elif self.options['bit_order'] == MSB_FIRST:
+ elif self.options['bit_order'] == 'msb-first':
self.databyte[rxtx] <<= 1
self.databyte[rxtx] |= (signal << 0)
else:
- raise Exception('Invalid bit order value: %d',
+ raise Exception('Invalid bit order value: %s',
self.options['bit_order'])
# Return here, unless we already received all data bits.
self.cur_data_bit[rxtx] += 1
return
- self.state[rxtx] = GET_PARITY_BIT
+ self.state[rxtx] = 'GET PARITY BIT'
self.put(self.startsample[rxtx], self.samplenum - 1, self.out_proto,
['DATA', rxtx, self.databyte[rxtx]])
def get_parity_bit(self, rxtx, signal):
# If no parity is used/configured, skip to the next state immediately.
- if self.options['parity_type'] == PARITY_NONE:
- self.state[rxtx] = GET_STOP_BITS
+ if self.options['parity_type'] == 'none':
+ self.state[rxtx] = 'GET STOP BITS'
return
# Skip samples until we're in the middle of the parity bit.
self.paritybit[rxtx] = signal
- self.state[rxtx] = GET_STOP_BITS
+ self.state[rxtx] = 'GET STOP BITS'
if parity_ok(self.options['parity_type'], self.paritybit[rxtx],
self.databyte[rxtx], self.options['num_data_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'] == PARITY_NONE else 1
+ skip_parity = 0 if self.options['parity_type'] == 'none' else 1
b = self.options['num_data_bits'] + 1 + skip_parity
if not self.reached_bit(rxtx, b):
return
['INVALID STOPBIT', rxtx, self.stopbit1[rxtx]])
# TODO: Abort? Ignore the frame? Other?
- self.state[rxtx] = WAIT_FOR_START_BIT
+ self.state[rxtx] = 'WAIT FOR START BIT'
# TODO: Fix range.
self.put(self.samplenum, self.samplenum, self.out_proto,
def decode(self, ss, es, data):
# TODO: Either RX or TX could be omitted (optional probe).
- for (samplenum, (rx, tx)) in data:
+ for (self.samplenum, pins) in data:
- # TODO: Start counting at 0 or 1? Increase before or after?
- self.samplenum += 1
+ # Ignore identical samples early on (for performance reasons).
+ if self.oldpins == pins:
+ continue
+ self.oldpins, (rx, tx) = pins, pins
# First sample: Save RX/TX value.
if self.oldbit[RX] == None:
for rxtx in (RX, TX):
signal = rx if (rxtx == RX) else tx
- if self.state[rxtx] == WAIT_FOR_START_BIT:
+ 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:
+ elif self.state[rxtx] == 'GET START BIT':
self.get_start_bit(rxtx, signal)
- elif self.state[rxtx] == GET_DATA_BITS:
+ elif self.state[rxtx] == 'GET DATA BITS':
self.get_data_bits(rxtx, signal)
- elif self.state[rxtx] == GET_PARITY_BIT:
+ elif self.state[rxtx] == 'GET PARITY BIT':
self.get_parity_bit(rxtx, signal)
- elif self.state[rxtx] == GET_STOP_BITS:
+ elif self.state[rxtx] == 'GET STOP BITS':
self.get_stop_bits(rxtx, signal)
else:
raise Exception('Invalid state: %d' % self.state[rxtx])
projects / libsigrokdecode.git / blobdiff