树莓PI发送串行通信 [英] Sending serial communication from Raspberry pi

问题描述

我从树莓派给一个Ar​​duino使用Python程序发送串行数据。我正在运行的Python 2.7.3。该计划是：

I am sending serial data from a Raspberry Pi to an Arduino using a Python program. I am running Python 2.7.3. The program is:

import serial

ser = serial.Serial('/dev/ttyACM0', 115200)

ser.write(b'\x4c\xff\x46')

的问题是，似乎没有任何如果它们在一个程序运行，以通过这三行发送。但是，如果我在Python shell中运行他们一行行，他们的工作很好。

The problem is that nothing seems to be sent by these three lines if they are run in a program. But if I run them line by line in a Python shell, they work fine.

另外，如果我有Arduino的串行监视器打开时，程序正常工作为好，但不运行线路逐一外壳。

Also, if I have the Arduino Serial Monitor open, the program works fine as well, without running the lines one by one in the shell.

编辑补充：

似乎没有在发送到Arduino一些延迟。所以，当我运行间pretive模式code，它的工作原理，但如果作为一个程序，它没有。我认为，因为我尝试在Windows机器上相同的程序。

It seems that there is some delay in sending to the Arduino. So when I run the code in interpretive mode, it works, but if as a program, it doesn't. I think that because I tried the same program on a Windows machine.

import serial

ser = serial.Serial('COM8', 115200)

ser.write(b'\x4c\x20\x46')

如果我在跑跨pretive模式下运行程序，甚至在上ser.write命令断点调试模式下，它的工作原理。但如果作为程序运行。

If I run the program in interpretive mode, or even in debugging mode with a breakpoint on the ser.write command, it works. But not if run as a program.

编辑，以增加更多的：

原来，Arduino的对串行通信的自动复位有被禁用：

It turns out that the Arduino has an auto-reset on serial communications that has to be disabled:

<一个href=\"http://playground.arduino.cc/Main/DisablingAutoResetOnSerialConnection#.UwP_wfldV8E\">http://playground.arduino.cc/Main/DisablingAutoResetOnSerialConnection#.UwP_wfldV8E

<一个href=\"http://forum.arduino.cc/index.php/topic,28723.0.html\">http://forum.arduino.cc/index.php/topic,28723.0.html

我用了RESET引脚与地之间的220 uF的电容。这样可行。

I used a 220 uF capacitor between the RESET pin and ground. That works.

很难通过这样的错误咬！它仍然智慧。

Tough to be bitten by a bug like that! It still smarts.

推荐答案

试试这个。如果你不能在空闲或等运行，键入蟒蛇name.py.尝试终端我也建议你来检查数据未来或/与RPI用腻子写是肯定的。

Try this. If you can't run it under idle or etc, try terminal by typing python name.py. I also suggest you to check the data coming or written from/to Rpi with putty to be sure.

import serial
import time


def readlineCR(port):
    rv = ""
    while True:
    ch = port.read()
    rv += ch
    if ch == '\r' or ch == '':
         return rv


port = serial.Serial("/dev/ttyAMA0", baudrate = 7200, timeout = 2)

while True: 
     rcv = readlineCR(port)
     port.write("I typed: " + repr(rcv))
     print(rcv)

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