pySerial读取丢失位

Question

我有以下串行端口的读写代码。但是当我频繁地运行它们时，比如说读写100次，总有一些时候读得到错误的字节数，它应该得到9个字节，但有时它只有8个字节。在

例如，通常当我发送[1，88，0，27，192]时，它应该返回9个字节，比如[1，88，4，0，0，3，35，182，49]。但是它总是在89次读写错误，它返回的值是[1，88，4，0，1，209，107，180]，少1个字节。当我检测到这是1个字节丢失后，我再次写入和读取相同的发送消息，如[1，88，0，27，192]，在这之后读取的数据总是丢失一个字节。但是，在其他语句之后，1字节丢失问题不会每次都出现。在

我遇到了另一个问题，比如，设备有时无法接收到我对特定命令的写入，具体地说，当我发送一个命令后，没有返回，因为我的串行设备没有接收到，所以它不能执行。所以我不得不关闭（）和open（）这样的端口，再发送几次命令，要使它返回aka excute命令，这样的重试花费了太多的时间，这让我再次等待。在

我的配置，FT232RL USB到串行芯片，9600波特率，8字节大小，超时1秒，停止位1，奇偶校验无。在

def SendData(self, portID, cmd):
        """
        cmd is the pre-defined variables , they are the lists in front of this file.
        After send data, there is a delay.
        """
        global command_count
        if (self.isOpen(portID)):
            command_count += 1
            lock = threading.RLock()
            with lock:
                try:
                    COMlogger.debug("SendData command count %d" % (command_count))
                    writereturn = self.serdict[portID].write(list2bytestr(cmd))
                    # wait for output buffer to drain, reference from the miniterm example
                    self.serdict[portID].flush()
                    self.lastcmd = cmd
                    COMlogger.debug("SendData sent out %s" % (str(cmd)))
                    COMlogger.debug("SendData write returns %d bytes." % writereturn)
                except:
                    COMlogger.error("Sending data to %s with ID %d failed." % (self.portaddresslist[portID], portID))
                    return False
                finally:
                    time.sleep(0.2)

            return True
        return False

    def GetData(self, portID):
        """
        It take times to let the device respond, so remember to wait a bit after sending data.
        Before get data, there is a deley
        """
        time.sleep(0.2)
        global command_count
        if (self.isOpen(portID)):
            lock = threading.RLock()
            with lock:
                try:
                    # possibly time out here
                    #receivedmsg = self.serdict[portID].readline() # stop using readline since it wait for the \n or time out.
                    text = self.serdict[portID].read(1)
                    if text:
                        time.sleep(0.2)
                        n = self.serdict[portID].inWaiting()
                        if n:
                            text += self.serdict[portID].read(n)
                    receivedmsg = text
                    COMlogger.debug("GetData from ID %d returned %s" %(portID, str(bytestr2list(receivedmsg))))
                    return receivedmsg
                except:
                    COMlogger.error( "Receiving data from %s with ID %d failed." % (self.portaddresslist[portID], portID))
                    return None
        else:
            COMlogger.error("Error in GetData, port %d is not open." % portID)
        return None