如何使用 pyserial 将文件逐行写入 com0com？

Posted 2023-02-23

【中文标题】如何使用 pyserial 将文件逐行写入 com0com？

【英文标题】：How can I write file line-by-line with pyserial to com0com?

【发布时间】：2019-10-19 20:31:19

【问题描述】：

我不能使用 pyserial 将文件中的多行数据写入虚拟 com 端口 (com0com)。我正在尝试逐行编写文件，以便可以同时更新 Tkinter 中的进度条。我在 Windows 上运行，并试图将写操作放在它自己的线程中（每个UART Controller with Tkinter and Python GUI）。我的程序写完一行就挂了。

相关代码：

import os
import sys
from functools import partial
import re
import time
import threading

import serial
import serial.tools.list_ports

import tkinter as tk
from tkinter import ttk, filedialog

class MainApp(tk.Tk):

    def __init__(self,
                 parent,
                 title = 'Main Application',
                 *args,
                 **kwargs):

        self.parent = parent

        #Set window title and size
        self.parent.title(title)

        #Create widget container
        container = tk.Frame(self.parent)

        #Add widgets

        # --> Create load program widgets
        load_frame = tk.LabelFrame(container,
                                   text = 'Load Program',
                                   width = 400,
                                   height = 100)

        port_dropdown = DropDown(load_frame,
                                 label = 'Port:',
                                 row = 0)

        file_browser = Browser(load_frame,
                               path_type = 'file',
                               label = 'File:',
                               row = 1)

        program_downloader = Downloader(load_frame,
                                        port_dropdown,
                                        file_browser,
                                        row = 2)

        # --> Layout load program widgets
        load_frame.grid(row = 0,
                        column= 0,
                        padx = (5,5),
                        pady = (5,5))

        #Layout widget container
        container.pack(fill = tk.BOTH,
                       padx = 10,
                       pady = 5,
                       expand = True)         
.
.
.

class Downloader(tk.Frame):

    def __init__(self,
                 parent,
                 port_dropdown,
                 file_browser,
                 row = 0):

        self.port_dropdown = port_dropdown
        self.file_browser = file_browser

        #Instantiate serial port object
        self.serial_port = None

        self.progress_bar = ttk.Progressbar(parent,
                                            orient = 'horizontal',
                                            mode = 'determinate')

        self.progress_bar.grid(row = row,
                               column = 0,
                               columnspan = 2,
                               padx = (5,5),
                               pady = (5,5),
                               sticky = 'WE')

        self.button = tk.Button(parent,
                                text = 'Download',
                                command = self.download_program)

        self.button.grid(row = row,
                         column = 2,
                         padx = (5,5),
                         pady = (5,5),
                         sticky = 'W')

    def download_program(self):

        port_full_name = self.port_dropdown.combobox.get()
        port_name = re.match('([^\s]+)', port_full_name).group(0)

        baud_rate = 9600

        program_path = self.file_browser.text.get()

        self.connect(port_name,
                     baud_rate,
                     program_path)

    def connect(self,
                port_name,
                baud_rate,
                program_path):

        self.serial_port = serial.Serial(port_name,
                                         baud_rate,
                                         timeout=1)

        t1 = threading.Thread(target = self.transfer_data,
                              args = (program_path,))
        t1.daemon = True
        t1.start()

    def transfer_data(self,
                      program_path):

        line = 1
        self.progress_bar['value'] = line

        with open(program_path, 'r') as program:

            max_lines = len(program.readlines())
            self.progress_bar['maximum'] = max_lines

        with open(program_path, 'r') as program:

            while line < max_lines:

                command = program.readline().replace('\n','\r\n')

                print(str(line) + ': ' + repr(command))

                self.serial_port.write(command.encode('ascii'))

                line += 1

                self.progress_bar['value'] = line

                self.serial_port.flush()

        print('done')
        self.disconnect()

    def disconnect(self):
        self.serial_port.close()

if __name__ == '__main__':

    #Initialize Tkinter
    root = tk.Tk()

    #Create GUI
    gui = MainApp(root,
                  'Main Application')

    #Run program
    root.mainloop()

GUI 挂起：

终端输出：

1: '@01\r\n'
2: '@02\r\n'

我能够在循环中第二次从program.txt 读取的事实告诉我，程序可能会挂起，因为端口仍停留在第一次写入时。

任何帮助将不胜感激。

【参考方案1】：

将timeout 和write_timeout 设置为0 可以防止阻塞，这似乎可以解决问题。