Question

我刚开始使用Python和Linux。

我用Python创建了一个程序，通过ttyS0与串行LCD通信，并创建了一个脚本来启动它。我禁用该行＆＃39;＃T0：2345：respawn：/ sbin / getty -L ttyS0 115200 vt100＆＃39;在inittab中防止出现问题。我得到的是不同的行为，这取决于我如何启动该程序。

当我在控制台模式下运行程序＆＃39; python /home/python/glv.py'一切正常。
当我在控制台模式下运行脚本启动程序时（/etc/init.d/glv.py）一切正常。
当我重新启动电路板时，脚本会在默认的运行级别3中启动，但我会连续超时与LCD通信。有时LCD显示一些输出，但通常对于发送到LCD的所有命令，我都会超时。我可以在日志中看到。

我无法使用其他ttyS *，因为还有其他设备使用它们。其他设备工作正常。我首先尝试使用inittab这样的＆＃39; null :: respawn：python /home/python/glv.py'但行为是一样的。

日志示例：

2014-10-06 13:48:30,407 - __main__ - DEBUG - ***************** 
2014-10-06 13:48:30,420 - __main__ - DEBUG - *** Start GLV *** 
2014-10-06 13:48:30,432 - __main__ - DEBUG - *****************
2014-10-06 13:48:30,444 - lcd - INFO - Initialize 
2014-10-06 13:48:35,492 - lcd - ERROR - Didn't receive an answer in ClearScreen 
2014-10-06 13:48:38,588 - lcd - ERROR - Didn't receive an answer in SetLandscape 
2014-10-06 13:48:41,635 - lcd - ERROR - Didn't receive an answer in SetBackgroundColor 
2014-10-06 13:48:44,681 - lcd - ERROR - Didn't receive an answer in SetForegroundColor 
2014-10-06 13:48:47,728 - lcd - ERROR - Didn't receive an answer in SetTextBackgroundColor 
2014-10-06 13:48:50,791 - lcd - ERROR - Didn't receive an answer in EnableTouchScreen 
2014-10-06 13:48:53,837 - lcd - ERROR - Didn't receive an answer in ClearScreen 
2014-10-06 13:48:56,884 - lcd - ERROR - Didn't receive an answer in ClearScreen 
2014-10-06 13:48:59,931 - lcd - ERROR - Didn't receive an answer in SetForegroundColorGreen 
2014-10-06 13:49:02,978 - lcd - ERROR - Didn't receive an answer in SetTextBackgroundColor1 
2014-10-06 13:49:06,024 - lcd - ERROR - Didn't receive an answer in preparing WriteTextPos

环境：

The Linux distro: PRETTY_NAME="Debian GNU/Linux 7 (wheezy)"
The Python version: Python 2.7.3 (default, Mar 23 2014, 01:44:56) 
The Hardware: Terra Board from ACME with AriaG25 
The command line in the script is just 'python /home/python/glv.py'

所以，任何人都知道为什么只有在重启后脚本启动程序时才能在LCD上获得超时？我自己无法弄清楚。

修改

作为设置LCD的BackgroundColor的示例：

def SetBackgroundColor(self):
    toSend = "\xFF\xA4\x19\xEB"
    state, res = self.SendBytesAndWaitResponse(toSend, "\x06", 3)
    if(state != 0):
        self.logger.error("Didn't receive an answer in SetBackgroundColor")

def SendBytesAndWaitResponse(self, toSend, toWait, timeout):
    strres = ""
    try:
        while(self.lockcomm):
            time.sleep(0.1)
        self.lockcomm = True
        start_time = time.time()
        end_time = start_time + timeout

        self.ser.write(toSend)
        while True:
            cur_time = time.time()
            if cur_time >= end_time:
                return (-1, strres)
            else:
                result = self.ser.read() 
                strres += result
                if(strres.find(toWait) != -1):
                    return (0, strres)
    except:
        return (-1, strres)
    finally:
        self.lockcomm = False

我发送4个字节，期望char并将超时设置为3秒（它很多）并且永远不会在3秒内得到LCD中实现的响应（char 0x06）。

Python脚本无法启动

0 个答案: