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我试图通过 pySerial 向 SIM800 模块发送 AT 命令。我遇到的问题是，当我发送命令时，我收到的消息是上一个命令的输出（或者有时是上一个命令本身）。我的代码如下所示：

import time
import serial

ser = serial.Serial()
ser.port = "/dev/ttyAMA0"
ser.baudrate = 9600
ser.open()

def readData():
    buffer = ""
    while True:
        oneByte = ser.read(1)
        if oneByte == b"\n":
            return buffer
        else:
            buffer += oneByte.decode("ascii")

def sendData(command, timeout):
    fullcommand = "{}\r\n".format(command)
    print "Sent: {}".format(fullcommand)
    ser.write(fullcommand)
    time.sleep(timeout)
    return

sendData("AT", 1) # Expecting "OK" back
print "Return: {}".format(readData()) # Prints AT

sendData("AT+CIPSHUT", 5) # Expecting "SHUT OK" back
print "Return: {}".format(readData()) # Prints OK

sendData("AT+CIPMUX=0", 2) # Expecting "OK" back
print "Return: {}".format(readData()) # Prints AT+CIPSHUT

sendData("AT+CSTT=\"myapn\"", 4) # Expecting "OK" back
print "Return: {}".format(readData()) # Prints SHUT OK

我觉得这与需要刷新缓冲区有关，但我对串行工作没有太多经验。谁能建议我做错了什么？

4

2 回答 2

3

通过 UART 与 SIM 800 通信时，我遇到了同样的问题。我使用 ATE0 命令禁用回声。试试这个它可能对你有帮助。

 import serial
 import time

 # dmesg | grep tty #to get which port it ts using
 port = serial.Serial("/dev/ttyO2", baudrate=9600, timeout=1)

 if port.isOpen():
     print(port.name + ' is open...!!!')

 # Transmitting AT Commands to the Modem
 port.write('AT'+'\r')
 print port.read(32)
 time.sleep(2)

 # To disable echo
 port.write('ATE0'+'\r')  
 print port.read(32)
 time.sleep(2)
于 2018-08-28T08:38:30.467 回答
2

一些东西。

  1. 如果要设置写入超时，则需要write_timeout在对象的初始化中Serial或通过设置来完成ser.write_timeout

  2. 如果您真的担心数据仍在输入缓冲区中，您可以这样做ser.reset_input_buffer()

  3. 如果您真的担心数据仍在输出缓冲区中，您可以这样做ser.reset_output_buffer()

现在在代码方面你可以做这样的事情

import time
import serial

ser = serial.Serial()
ser.port = "/dev/ttyAMA0"
ser.baudrate = 9600
ser.open()

def readData():
    buffer = ""
    while True:
        oneByte = ser.read(1)
        if oneByte == b"\n":
            return buffer
        else:
            buffer += oneByte.decode("ascii")

def sendData(command, timeout):
    fullcommand = "{}\r\n".format(command)
    ser.write_timeout = timeout # This is where you can set the timeout
    bytes_written = ser.write(fullcommand)
    # Check to see if all the data was written
    if bytes_written == len(fullcommand):
        print "Sent: {}".format(fullcommand)
    else:
        print 'Not all data transferred'

sendData("AT", 1) # Expecting "OK" back
print "Return: {}".format(readData()) # Prints AT

sendData("AT+CIPSHUT", 5) # Expecting "SHUT OK" back
print "Return: {}".format(readData()) # Prints OK

sendData("AT+CIPMUX=0", 2) # Expecting "OK" back
print "Return: {}".format(readData()) # Prints AT+CIPSHUT

sendData("AT+CSTT=\"myapn\"", 4) # Expecting "OK" back
print "Return: {}".format(readData()) # Prints SHUT OK
于 2018-04-25T16:54:50.090 回答