Python脚本没有

Question

我只是从Python和Linux开始。在

我用Python编写了一个通过ttyS0与串行LCD通信的程序，并编写了一个在启动时启动它的脚本。为了防止出现问题，我禁用了inittab中的行“#T0:2345:respawn:/sbin/getty-L ttyS0 115200 vt100”。我得到的是不同的行为，这取决于我如何启动程序。在

1. 当我在控制台模式下运行程序时'python/home/python/glv.py公司“一切正常。在
2. 当我在控制台模式下运行脚本时，它将启动程序（/etc/init.d/glv.py公司)一切正常。在
3. 当我重新启动电路板时，脚本以默认运行级别3启动，但我有连续的超时与LCD通信。有时LCD会显示一些输出，但通常发送到LCD的所有命令都会超时。我可以在日志中看到。在

我不能使用其他的TTY*因为还有其他设备在使用它们。其他设备工作正常。 我首先尝试像这样使用inittab'null:：重生：python/home/python/glv.py“但行为是一样的。在

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：

^{pr2}$

所以，有人知道为什么只有当程序在重启后由脚本启动时，LCD才会出现超时？ 我自己想不出来。在

编辑：

例如，设置LCD的背景色：

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个字节的字符，并将超时设置为3秒（这太多了），但在这3秒钟内，我从来没有得到LCD上实现的响应（char 0x06）。在