在 Python 3.3 中使用 pySerial
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Using pySerial with Python 3.3
提问by P_Rein
I've seen many code samples using the serial port and people say they are working codes too. The thing is, when I try the code it doesn't work.
我已经看到许多使用串行端口的代码示例，人们说他们也在工作代码。问题是，当我尝试代码时，它不起作用。
import serial
ser = serial.Serial(
port=0,
baudrate=9600
# parity=serial.PARITY_ODD,
# stopbits=serial.STOPBITS_TWO,
# bytesize=serial.SEVENBITS
)
ser.open()
ser.isOpen()
print(ser.write(0xAA))
The error it gives me is : "SerialException: Port is already opened". Is it me using python3.3 the problem or is there something additional I need to instal ? Is there any other way to use COM ports with Python3.3 ?
它给我的错误是：“SerialException：端口已打开”。是我使用 python3.3 的问题还是我需要安装一些额外的东西？有没有其他方法可以在 Python3.3 中使用 COM 端口？
采纳答案by P_Rein
So the moral of the story is.. the port is opened when initialized. ser.open()fails because the serial port is already opened by the ser = serial.Serial(.....). And that is one thing.
所以这个故事的寓意是..端口在初始化时打开。ser.open()失败，因为串口已经被ser = serial.Serial(.....). 这是一回事。
The other problem up there is ser.write(0xAA)- I expected this to mean "send one byte 0xAA", what it actually did was send 170(0xAA) zeros. In function write, I saw the following :
data = bytes(data)where data is the argument you pass. it seems the function bytes() doesn't take strings as arguments so one cannot send strings directly with: serial.write(), but ser.write(bytearray(TheString,'ascii'))does the job.
另一个问题是ser.write(0xAA)- 我预计这意味着“发送一个字节 0xAA”，它实际上做的是发送 170(0xAA) 个零。在函数中write，我看到了以下内容：
data = bytes(data)其中 data 是您传递的参数。似乎函数 bytes() 不接受字符串作为参数，因此不能直接使用: 发送字符串serial.write()，但可以ser.write(bytearray(TheString,'ascii'))完成这项工作。
Although I am considering adding:
虽然我正在考虑添加：
if(type(data) == type('String')):
data = bytearray(data,'ascii')
in ser.write(), although that would make my code not work on other PCs.
in ser.write()，尽管这会使我的代码无法在其他 PC 上运行。
