在 pyserial 中使用 xonxoff-flow 控制 [英] Using xonxoff-flow control with pyserial

问题描述

我目前正在尝试与一台有点旧的 HP 打印机模型进行交互，这为我提供了两种可能的流量控制方法:完全没有流量控制或基于软件的流量控制 (XON/XOFF).

我正在使用以下命令初始化 pySerial 并仅使用一个普通的大字符串将我的数据写入端口:

serial = serial.Serial(port = '/dev/ttyUSB3', baudrate = 9600, parity = serial.PARITY_ODD, stopbits = serial.STOPBITS_ONE, bytesize = serial.EIGHTBITS)

这工作正常 - 但有一个问题:流量控制似乎被完全忽略，数据被发送和发送 - 这导致设备出现 IO 缓冲区溢出并停止工作.

我的第一个想法是，如果我使用 serial.write('unbelivable long string')，pySerial 可能无法停止传输，所以我将字符串分成块并发送:

data = ['command', 'another command', 'more commands', '你得到了漂移......']对于我在数据中:串行写入(i)

嗯……这也行不通.

所以基本上我可以将波特率更改为较低的值，以便设备比传输速度更快，或者每隔几块添加一次睡眠之类的东西......但我想，这不是人们应该这样做的方式.

所以...任何人来解释我，我做错了什么?;-)

谢谢，

马丁

解决方案

您忘记了 xonxoff 参数.xonxoff=真

http://pyserial.readthedocs.io/en/latest/pyserial_api.html

I am currently trying to interface with a somewhat old old model of a HP-printer which gives me two possible methods of flow-control: No flow control at all or software-based flow control (XON/XOFF).

I am initializing pySerial with the following command and just justing a plain big string to write my data to the port:

serial = serial.Serial(port = '/dev/ttyUSB3', baudrate = 9600, parity = serial.PARITY_ODD, stopbits = serial.STOPBITS_ONE, bytesize = serial.EIGHTBITS)

This works fine - but there is a catch: it seems like the flow-control is completly ignored and data is sent and sent - which results in the device having a IO-buffer-overflow and stop working.

My first thought was, that if I use serial.write('unbelivable long string'), pySerial might not be able to cease transmission, so I split up the string into chunks and sent it:

data = ['command', 'another command', 'more commands', 'you get the drift...']
for i in data:
    serial.write(i)

Well... This doesn't work either.

So basically I could just change the baud-rate to something lower so the device is faster than the transmission or just add something like a sleep every few chunks... But I guess, this is not how one should do it.

So... Anyone in to explain me, what am I doing wrong? ;-)

Thanks,

Martin

解决方案

You forgot the xonxoff parameter. xonxoff=True

http://pyserial.readthedocs.io/en/latest/pyserial_api.html

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