pySerial问题:嵌入式控制器停止回显命令

我正在尝试使用在Ubuntu主机上运行的pySerial来自动测试嵌入式控制器。我可以在终端窗口(例如PuTTY)中输入命令,并全天从EC获得响应。然而,当我尝试使用pySerial程序来做同样的事情时,EC会在一段时间后停止回显命令,就在回显命令的中间。从那时起,EC停止对程序的响应,包括不发送被中断的命令的结果。

如果我终止程序并尝试再次使用终端连接到EC,则EC没有响应。如果发生外部事件,导致EC将输出写入终端,则该信息将正确显示。问题一直存在,直到我重新启动EC——这也会删除问题发生时EC上发生的任何日志。(日志只能通过串行端口访问…)

似乎pySerial正在执行的某些操作导致EC的输入处理停止。我试着输入Ctrl-Q(XON),希望有一些不明显的软件流控制,但这并没有什么区别。我尝试过在程序中发送交替的命令,在发送命令之间发送空行,在命令发送之间插入延迟——但每次处理几个命令后,它都会失效。

这是我目前正在使用的脚本:

import serial
from datetime import datetime

ser = serial.Serial('/dev/ttyUSB0', 115200, timeout=1)

print('Starting up')
# send an empty command to ensure a prompt is displayed
ser.write(b'\r\n')

commandToSend = 'battery current'
failed = 0
running = True
while running:
    while running:
        # read from the EC until a timeout occurs with no data available
        try:
            # wait for the EC prompt
            rcvData = ser.read_until(b' ec> ')
            now = datetime.now().time()
            print('{}\tRead from device: "{}"'.format(now, rcvData))
            decoded = rcvData.decode('ascii')
            if len(decoded) == 0:
                # timeout, nothing read from EC, send next command
                failed += 1
                break
            # normalize line terminations then split the data into lines
            lines = decoded.replace('\r\r\n','\r\n').split('\r\n')
            for line in lines:
                print('{}{}'.format(' '*34, line))
            break
        except KeyboardInterrupt:
            print('\nKeyboard interrupt, aborting')
            running = False
            break
        except Exception as e:
            print(e)  # this branch never executes, from my observation
            pass
    now = datetime.now().time()
    if failed > 1:
        print('{}\tCommunication with the EC has failed'.format(now))
        break
    if running:
        # send the command when there's no data to read
        print('{}\tWriting: "{}\\r\\n"'.format(now, commandToSend))
        ser.write('{}\r\n'.format(commandToSend).encode())
        ser.flush()

运行上述脚本的典型结果是:

$ ./ec-uart-test.py
Starting up
20:19:10.620998     Read from device: "b'\r\n ec> '"
                              
                                   ec> 
20:19:11.622234     Read from device: "b''"
20:19:11.622345     Writing: "battery current\r\n"
20:19:11.627921     Read from device: "b'\r\n ec> '"
                              
                                   ec> 
20:19:11.628690     Read from device: "b'battery current\r\n0ma\r\r\n ec> '"
                                  battery current
                                  0ma
                                   ec> 
20:19:11.628777     Writing: "battery current\r\n"
20:19:11.635899     Read from device: "b'\r\n ec> '"

                                   ec> 
20:19:12.637335     Read from device: "b'battery cu'"
                                  battery cu
20:19:12.637439     Writing: "battery current\r\n"
20:19:13.644800     Read from device: "b''"

20:19:14.646080     Read from device: "b''"
20:19:14.646172     Communication with the EC has failed

除了破解EC并在其上安装硬件分析器之外,我还应该尝试其他方法来让这些代码正常工作吗?