def bsl(self, cmd, message='', expect=None):
self.bsl_header(cmd, message)
if self.extra_timeout is None:
head = self.serial.read(3)
else:
for timeout in range(self.extra_timeout):
head = self.serial.read(3)
if head:
break
if len(head) != 3:
raise bsl5.BSL5Timeout('timeout while reading answer (header)')
pi, length = struct.unpack("<BH", head)
if pi == 0x80:
data = self.serial.read(length)
if len(data) != length:
raise bsl5.BSL5Timeout('timeout while reading answer (data)')
crc_str = self.serial.read(2)
if len(crc_str) != 2:
raise bsl5.BSL5Timeout('timeout while reading answer (CRC)')
crc = struct.unpack("<H", crc_str)
crc_expected = reduce(crc_update, data, 0xffff)
crc_expected = struct.pack('<H', crc_expected)
if crc_str != crc_expected:
raise bsl5.BSL5Exception('CRC error in answer')
if expect is not None and length != expect:
raise bsl5.BSL5Error('expected %d bytes, got %d bytes' %
(expect, len(data)))
return data
else:
if pi:
raise bsl5.BSL5Error(
'received bad PI, expected 0x80 (got 0x%02x)' % (pi))
raise bsl5.BSL5Error(
'received bad PI, expected 0x80 (got empty response)')
def bsl(self, cmd, message='', expect=None):
"""\
Low level access to the serial communication.
This function sends a command and waits until it receives an answer
(including timeouts). It will return a string with the data part of
the answer. In case of a failure read timeout or rejected commands by
the slave, it will raise an exception.
If the parameter "expect" is not None, "expect" bytes are expected in
the answer, an exception is raised if the answer length does not match.
If "expect" is None, the answer is just returned.
Frame format:
+-----+----+----+-----------+----+----+
| HDR | LL | LH | D1 ... DN | CL | CH |
+-----+----+----+-----------+----+----+
"""
# first synchronize with slave
self.logger.debug('Command 0x%02x %s' % (cmd, message.encode('hex')))
# prepare command with checksum
txdata = struct.pack('<BHB', 0x80, 1 + len(message), cmd) + message
txdata += struct.pack('<H',
functools.reduce(crc_update, txdata,
0xffff)) # append checksum
#~ self.logger.debug('Sending command: %r' % (txdata.encode('hex'),))
# transmit command
self.serial.write(txdata)
# wait for command answer
if self.blindWrite:
time.sleep(0.100)
return
if self.ignore_answer:
return
self.logger.debug('Reading answer...')
if self.extra_timeout is None:
ans = self.serial.read(1)
else:
for timeout in range(self.extra_timeout):
ans = self.serial.read(1)
if ans:
break
if ans != BSL5_ACK:
if ans:
raise bsl5.BSL5Error(
'BSL reports error: %s' %
BSL5_UART_ERROR_CODES.get(ans, 'unknown error'))
raise bsl5.BSL5Error('No ACK received (timeout)')
head = self.serial.read(3)
if len(head) != 3:
raise bsl5.BSL5Timeout('timeout while reading answer (header)')
pi, length = struct.unpack("<BH", head)
if pi == '\x80':
data = self.serial.read(length)
if len(data) != length:
raise bsl5.BSL5Timeout('timeout while reading answer (data)')
crc_str = self.serial.read(2)
if len(crc_str) != 2:
raise bsl5.BSL5Timeout('timeout while reading answer (CRC)')
crc = struct.unpack("<H", crc_str)
crc_expected = functools.reduce(crc_update, head + data, 0xffff)
if crc != crc_expected:
raise bsl5.BSLException('CRC error in answer')
if expect is not None and length != expect:
raise bsl5.BSL5Error('expected %d bytes, got %d bytes' %
(expect, len(data)))
return data
else:
if pi:
raise bsl5.BSL5Error(
'received bad PI, expected 0x80 (got 0x%02x)' %
(ord(pi), ))
raise bsl5.BSL5Error(
'received bad PI, expected 0x80 (got empty response)')
