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我正在尝试使用 Pyserial 从串行端口读取通过蓝牙调制解调器发送的数值。我是 Python 的初学者,并找到了一个我正在尝试使用的好例子。

from threading import Thread
import time
import serial

last_received = ''
def receiving(ser):
    global last_received
    buffer = ''
    while True:
        buffer = buffer + ser.read(ser.inWaiting())
        if '\n' in buffer:
            lines = buffer.split('\n') # Guaranteed to have at least 2 entries
            last_received = lines[-2]
            #If the modem sends lots of empty lines, you'll lose the
            #last filled line, so you could make the above statement conditional
            #like so: if lines[-2]: last_received = lines[-2]
            buffer = lines[-1]


class SerialData(object):
    def __init__(self, init=50):
        try:
            self.ser = ser = serial.Serial(
            port='/dev/tty.FireFly-16CB-SPP',
            baudrate=115200,
            stopbits=serial.STOPBITS_ONE,
            bytesize=serial.EIGHTBITS
            )
        except serial.serialutil.SerialException:
            #no serial connection
            self.ser = None
        else:
            Thread(target=receiving, args=(self.ser,)).start()

    def next(self):
        if not self.ser:
            return 140 #return anything so we can test when Arduino isn't connected
        #return a float value or try a few times until we get one
        for i in range(40):
            raw_line = last_received
            try:
                return float(raw_line.strip())
            except ValueError:
                print 'bogus data',raw_line
                time.sleep(.005)
        return 0.
    def __del__(self):
        if self.ser:
            self.ser.close()

if __name__=='__main__':
    s = SerialData()
    for i in range(500):
        time.sleep(.015)
        print s.next()

我可以在另一个程序中打开端口,并可以从中发送/接收数据。但是,上面的代码似乎并没有打开端口,只是向终端窗口重复“100”500次,但我不知道它来自哪里,也不知道为什么端口没有正确打开。打开端口没有延迟,因为它在另一个程序上,所以我什至不知道它是否试图打开。

我不知道还能尝试什么,或者错误在哪里,所以我正在寻求帮助。我究竟做错了什么?

4

1 回答 1

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except serial.serialutil.SerialException:

您正在捕获并消除连接中的错误。注释掉这个块,看看它是否产生错误信息。

于 2011-03-30T17:47:25.067 回答