Python 2.7 Pyserial readline()永远挂起程序,而不读取串行数据
调用pyserial.readline()函数时,我的程序挂起。我对程序进行了跟踪,底部循环不断重复Python 2.7 Pyserial readline()永远挂起程序,而不读取串行数据,python-2.7,pyserial,trace,rs485,Python 2.7,Pyserial,Trace,Rs485,调用pyserial.readline()函数时,我的程序挂起。我对程序进行了跟踪,底部循环不断重复 transport.py(47): self.sensor_data = self.serif.readline() --- modulename: serialposix, funcname: read serialposix.py(477): if not self.is_open: serialposix.py(479): read
transport.py(47): self.sensor_data = self.serif.readline()
--- modulename: serialposix, funcname: read
serialposix.py(477): if not self.is_open:
serialposix.py(479): read = bytearray()
serialposix.py(480): timeout = Timeout(self._timeout)
--- modulename: serialutil, funcname: __init__
serialutil.py(125): self.is_infinite = (duration is None)
serialutil.py(126): self.is_non_blocking = (duration == 0)
serialutil.py(127): self.duration = duration
serialutil.py(128): if duration is not None:
serialutil.py(129): self.target_time = self.TIME() + duration
serialposix.py(481): while len(read) < size:
serialposix.py(482): try:
serialposix.py(483): ready, _, _ = select.select([self.fd, self.pipe_abort_read_r], [], [], timeout.time_left())
--- modulename: serialutil, funcname: time_left
serialutil.py(139): if self.is_non_blocking:
serialutil.py(141): elif self.is_infinite:
serialutil.py(144): delta = self.target_time - self.TIME()
serialutil.py(145): if delta > self.duration:
serialutil.py(150): return max(0, delta)
serialposix.py(484): if self.pipe_abort_read_r in ready:
serialposix.py(491): if not ready:
serialposix.py(493): buf = os.read(self.fd, size - len(read))
serialposix.py(496): if not buf:
serialposix.py(503): read.extend(buf)
serialposix.py(516): if timeout.expired():
--- modulename: serialutil, funcname: expired
serialutil.py(135): return self.target_time is not None and self.time_left() <= 0
--- modulename: serialutil, funcname: time_left
serialutil.py(139): if self.is_non_blocking:
serialutil.py(141): elif self.is_infinite:
serialutil.py(144): delta = self.target_time - self.TIME()
serialutil.py(145): if delta > self.duration:
serialutil.py(150): return max(0, delta)
serialposix.py(481): while len(read) < size:
serialposix.py(518): return bytes(read)
在启动read函数之前,我尝试添加函数self.serif.reset\u input\u buffer()
,但这似乎让事情变得更糟
下面是readline()
函数前面的函数副本
def rcv_data(self):
"""Receives data, cleans it and returns it to main()"""
# CHECKS FOR DATA IN BUFFER
serial_buffer = self.serif.inWaiting()
if serial_buffer > 0:
cnt = 0
print("serial_buffer = %i" % serial_buffer)
while self.serif.read().encode('hex') != '02':
cnt += 1
serial_buffer -= 1
print("Eliminated %i peices of garbage" % (cnt))
# Reads data from the buffer
self.sensor_data = self.serif.readline()
我不明白为什么这段代码似乎卡在serialposix.py循环中。。如果有人能帮我,我将不胜感激
谢谢,如果我需要发送更多信息,请告诉我。编辑
我以前为什么让它工作已经不再是个谜了。为我的设备和RS485电路上拉/下拉电阻器供电的电源不稳定。因此,我在我的SOF或EOF应该在的地方收到了噪音,所以程序一直在读。尽管如此,我仍然保留了下面的变通方法,因为它更清楚我在做什么(尽管更长…)
此外,我在下面的答案中添加了一个中断,以防在一定数量的读取周期中找不到SOF或EOF
编辑结束
不是一个特别的答案,而是一个解决办法。我将首先强调以下几点
\n
(0x11
,十六进制)i和我的串行数据从未提供此值。我以前为什么让它工作是个谜def readline(self):
SOF = '02'
EOF = '03'
# FIND START OF FRAME
while serif.read().encode('hex') != SOF:
continue
# RECORD UNTIL END OF FRAME
while True:
temp = serif.read()
if temp.encode('hex') == EOF:
break
else:
sensor_data += temp
我原来的函数现在看起来像这样
def rcv_data(self):
"""Receives data cleans it and returns it to main()"""
# CHECKS FOR DATA IN BUFFER
if serif.inWaiting() > 0:
readline()
return sensor_data
def rcv_data(self):
"""Receives data cleans it and returns it to main()"""
# CHECKS FOR DATA IN BUFFER
if serif.inWaiting() > 0:
readline()
return sensor_data