python 串口訪問模塊...

xiaoqdu 2008-12-10

展開全文

使用python操作串口

一、

為了使用python操作串口，首先需要下載相關模塊:

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

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

二、

google “python 串口操作”關鍵字，找到相關python代碼，

我是從http://currentlife.blog.sohu.com/53741351.html頁面上拷貝的代碼。

咱得參考人家的代碼修改。

三、

發(fā)送數據可用chr和pack組裝處理，如：

snd = ''

snd += chr(97)

data = 0x12345678

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

snd += chr(0x64)

self.l_serial.write(snd);

#發(fā)送的數據是(16進制)：61 78 56 34 12 64

接收的數據用ord函數，將字節(jié)內容變?yōu)檎麛?，進行判斷處理。

如：if ord(recv[2])== 0x01:

判斷recv[2]是否是0x01.

注意：不能這樣比較

if recv[2] == 'a':

pass

也不能這樣比較

if recv[2] == 0x97:

pass

因為python的字符串存儲機制我不清楚，所以不知道為什么這樣比較不可以。

帖點代碼，依據前面的參考代碼修改的：

#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:
            # 接收間隔
            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]),

                    # 發(fā)送數據
                    snddata = '';
                    snddata += chr(97)
                    tt = 0x12345678;
                    snddata += pack('i', tt)
                    snddata += chr(0x64)
                    self.l_serial.write(snddata);

                # 判斷結束
                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();

#測試用部分
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;