python 串口访问模块...

使用python操作串口

 

一、

为了使用python操作串口，首先需要下载相关模块:

1. pyserial (http://pyserial.wiki./pySerial)

2. pywin32 (http:///projects/pywin32/)

 

二、

google “python 串口 操作”关键字，找到相关python代码，

我是从http://currentlife.blog.sohu.com/53741351.html页面上拷贝的代码。

咱得参考人家的代码修改。

 

 

三、

发送数据可用chr和pack组装处理，如：

snd = ''

snd += chr(97)

data = 0x12345678

snd += pack.('i', data)

snd += chr(0x64)

self.l_serial.write(snd);

#发送的数据是(16进制)：61 78 56 34 12 64

 

接收的数据用ord函数，将字节内容变为整数，进行判断处理。

如：if ord(recv[2])== 0x01:

判断recv[2]是否是0x01.

 

 

注意：不能这样比较

if recv[2] == 'a':

   pass

也不能这样比较

if recv[2] == 0x97:

   pass

 

因为python的字符串存储机制我不清楚，所以不知道为什么这样比较不可以。

 

帖点代码，依据前面的参考代码修改的：

#coding=gb18030

import sys,threading,time;
import serial;
import binascii,encodings;
import re;
import socket;
from struct import *;

class ComThread:
    def __init__(self, Port=0):
        self.l_serial = None;
        self.alive = False;
        self.waitEnd = None;
        self.port = Port;

    def waiting(self):
        if not self.waitEnd is None:
            self.waitEnd.wait();

    def SetStopEvent(self):
        if not self.waitEnd is None:
            self.waitEnd.set();
        self.alive = False;
        self.stop();

    def start(self):
        self.l_serial = serial.Serial();
        self.l_serial.port = self.port;
        self.l_serial.baudrate = 9600;
        self.l_serial.timeout = 2;
        self.l_serial.open();

        if self.l_serial.isOpen():
            self.waitEnd = threading.Event();
            self.alive = True;
            self.thread_read = None;
            self.thread_read = threading.Thread(target=self.FirstReader);
            self.thread_read.setDaemon(1);
            self.thread_read.start();
            return True;
        else:
            return False;

    def FirstReader(self):
        while self.alive:
            # 接收间隔
            time.sleep(0.1);
            try:
                data = '';
                n = self.l_serial.inWaiting();
                if n:
                    data = data + self.l_serial.read(n);
                    for l in xrange(len(data)):
                        print '%02X' % ord(data[l]),

                    # 发送数据
                    snddata = '';
                    snddata += chr(97)
                    tt = 0x12345678;
                    snddata += pack('i', tt)
                    snddata += chr(0x64)
                    self.l_serial.write(snddata);

                # 判断结束
                if len(data) > 0 and ord(data[len(data)-1])==0x45:
                    #pass;
                    break;
               
            except Exception, ex:
                print str(ex);

        self.waitEnd.set();
        self.alive = False;

    def stop(self):
        self.alive = False;
        self.thread_read.join();
        if self.l_serial.isOpen():
            self.l_serial.close();

 

#测试用部分
if __name__ == '__main__':
    rt = ComThread();
    try:
        if rt.start():
            rt.waiting();
            rt.stop();
        else:
            pass;            
    except Exception,se:
        print str(se);

   

    if rt.alive:
        rt.stop();

    print '';
    print 'End OK .';
    del rt;