使用 PySerial 从串口读取二进制数据

发布于 2024-11-01 10:19:53 字数 991 浏览 1 评论 0原文

PyQT 4.7 没有从 QIODevice 继承的类，允许直接与串行端口通信（例如 QSerialDevice）。所以我认为使用 QProcess 类并从不同的进程实现对串行端口的实际读/写会更容易，该进程将使用 QProcess 接口与我的主 QT 应用程序进行交互。

现在的问题是，当我使用下面的代码时，发送和接收的字节数不一样。 所以我的问题是如何从串行端口正确读取二进制数据，然后将所有内容转发到标准输出？

这是我创建 QProcess 的主 QT 程序的摘录：

        self.micromouse_socket = QProcess()
        self.micromouse_socket.start("/home/ansis/Source/Perforce-pele/Pele/tools/console/comtalker.py", "")
        self.micromouse_socket.started.connect(self.on_micromouse_socket_started)
        self.label_8.setText("Starting COM...")

这是会说话的进程使用串行端口（comtalker.py；非阻塞部分尚未完成）：

#!/usr/bin/python
import serial
import sys

if __name__ == "__main__":

    ser = serial.Serial(0)

    while 1 :
        x = ser.read(1)
        sys.stdout.write(x)
        sys.stdout.flush()

PS 问题可能出在其他地方，而不是在 PySerial 中。在另一台计算机上，我使用此命令“./binary_data_generator > /dev/ttyS0”写入 ttyS0。当我只发送 ASCII 字符（文本+数字）时，相同的代码似乎工作正常

原文

PyQT 4.7 does not have inherited class from QIODevice that allows to talk with serial port directly (e.g. QSerialDevice). So I thought that it would be easier for me to use QProcess class and implement the actual reading/writing to serial port from a different process that will interface with my main QT application using QProcess interface.

Now the problem is that amount of bytes sent and received is not the same when I am using the code below. So my question is how to correctly read binary data from a serial port and then forward everything to the stdout?

This is an excerpt from my main QT program that creates QProcess:

        self.micromouse_socket = QProcess()
        self.micromouse_socket.start("/home/ansis/Source/Perforce-pele/Pele/tools/console/comtalker.py", "")
        self.micromouse_socket.started.connect(self.on_micromouse_socket_started)
        self.label_8.setText("Starting COM...")

And this is the Process that will talk with Serial port (comtalker.py; non blocking part is not yet finished):

#!/usr/bin/python
import serial
import sys

if __name__ == "__main__":

    ser = serial.Serial(0)

    while 1 :
        x = ser.read(1)
        sys.stdout.write(x)
        sys.stdout.flush()

P.S. It could be that problem is somewhere else and not in PySerial. On the other computer I am writing to ttyS0 with this command "./binary_data_generator > /dev/ttyS0". The same code seemed to work fine when I was sending only ASCII characters (text+numbers)

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提笔落墨 2024-11-08 10:19:53

看来 PySerial （或 Pyserial 依赖的库）正在将单个“0x0a”（\n）字符转换为两个字符“0x0d 0x0a”（\r\n）。两个通信端点都在 Linux 上运行，所以我不确定为什么有人想要翻译这些行结尾...

这里 strace 表明发送者只发送 \n 到 ttyS0：

write(1, "M\n", 2)                      = 2
write(1, "\n", 1)                       = 1
write(1, "M\n", 2)                      = 2
write(1, "\n", 1)                       = 1

在调试 PySerial 输出时，我看到每个\n 以 \r 为前缀。

在声称这是一个错误之前，我将做进一步的调查，找出谁以及为什么添加这个回车符......

It seems that PySerial (or a library that Pyserial depends on) is translating a single "0x0a" (\n) character into two characters "0x0d 0x0a"(\r\n). Both communication end-points are running on Linux, so I am not sure why someone would like to even translate those line endings at all...

Here strace indicates that sender sends only \n to ttyS0:

write(1, "M\n", 2)                      = 2
write(1, "\n", 1)                       = 1
write(1, "M\n", 2)                      = 2
write(1, "\n", 1)                       = 1

While debugging PySerial output I saw that each \n is prefixed with a \r.

Before claiming that this as a Bug I will do further investigation to find out who and why adds this carriage return...

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