串口模块的波特率比较特别，找了几个串口工具都不支持。。。所以，干脆用python自己来写了，其实已经好奇好久了，别人的工具各种不顺手。
需要pyserial的支持，兼容各种平台，不需要新编译二进制文件。
先贴一个定时发送的代码：
import serial import time ser = serial.Serial('/dev/ttyUSB0', 250000, timeout=1) print ser.isOpen() words="gggggggggggggggg" while (1): print "send 256x""+words+"" to remotes" startTime = time.time() times = 256 while (times): times -= 1 s = ser.write(words) endTime = time.time() print "use time: "+str(endTime-startTime) print "" time.sleep(5) ser.close()
然后是一些其它的方法：
1. 使用序号打开串口：ser = serial.Serial(0) 。but，怎么确定串口的序号？？？
2. 查看串口的名称，啊哈，用1的方法打开串口后，你可以产看串口的名字：print ser.portstr
3. 先例化一个实体，再打开：
>>> ser = serial.Serial() >>> ser.baudrate = 19200 >>> ser.port = 0 >>> ser Serial<id=0xa81c10, open=False>(port='COM1', baudrate=19200, bytesize=8, parity='N', stopbits=1, timeout=None, xonxoff=0, rtscts=0) >>> ser.open() >>> ser.isOpen() True >>> ser.close() >>> ser.isOpen() False
好多人问 windows 下面提示设备不存在！亲，windows 下面的串口设备名不一样的啊，上面的代码里面 COM1 就是 windows 下面的设备。
4. 读取数据的几种方式
>>> ser = serial.Serial('/dev/ttyS1', 19200, timeout=1) >>> x = ser.read() # read one byte >>> s = ser.read(10) # read up to ten bytes (timeout) >>> line = ser.readline() # read a '/n' terminated line >>> ser.close()
其中，如果只是串口调试，直接ser.read(1000)，这样会把读到的值直接打印到屏幕上。
5.所有参数
ser = serial.Serial( port=None, # number of device, numbering starts at # zero. if everything fails, the user # can specify a device string, note # that this isn't portable anymore # if no port is specified an unconfigured # an closed serial port object is created baudrate=9600, # baud rate bytesize=EIGHTBITS, # number of databits parity=PARITY_NONE, # enable parity checking stopbits=STOPBITS_ONE, # number of stopbits timeout=None, # set a timeout value, None for waiting forever xonxoff=0, # enable software flow control rtscts=0, # enable RTS/CTS flow control interCharTimeout=None # Inter-character timeout, None to disable )
6. exception：serial.SerialException
另一个完整收发的例子，单片机数据以TLV（Type，Length，Value）格式发上来
#!/usr/bin/env python
# it's a program of luo, piedgogo@sina.com
import serial import array import os import signal from time import sleep flag_stop = False def onsignal_int(a,b): print "sigint!" global flag_stop flag_stop = True signal.signal(signal.SIGINT, onsignal_int)
signal.signal(signal.SIGTERM, onsignal_int) ser = serial.Serial('/dev/ttyUSB0', 9600, timeout = 0.001) print "serial.isOpen() =",ser.isOpen() cmd_send = "7b02000129cc00c80378290400640000cc7d0d0a" cmd_send = cmd_send.decode("hex") stop = "7b04047d0d0a" stop = stop.decode("hex") cmd_back = "" cmd_length = 0x00 cmd_count = 0x00 s = ser.write(cmd_send) while True: sleep(0.1) if flag_stop: # read data until Ctrl+c ser.write(stop) # send cmd stop before exit print "reset cmd has been sent!" sleep(0.05) break text = ser.read(1) # read one, with timout if text: # check if not timeout n = ser.inWaiting() # look if there is more to read if n: text = text + ser.read(n) #get it cmd_back = cmd_back + text text = "" if len(cmd_back) < 2: # go back if no enough data recvd continue if cmd_length == 0x00: # new loop cmd_length = ord(cmd_back[1]) # Type(1 byte),Length of Value(1 byte),Value print "new cmd length,",cmd_length if (cmd_length + 0x02) > len(cmd_back): # do nothing until all bytes is recvd continue # so far, we have got a full cmd
hex_list = [hex(ord(i)) for i in cmd_back] # more readable than data.encode("hex") print "In buffer:",hex_list
cmd_back = cmd_back[cmd_length+2:] # remove this cmd(TLV) from buffer cmd_length = 0 cmd_count += 1
print "==> %d cmds recvd."%(cmd_count) print "-------------" ser.close()
可用的串口列表，可以用下面的方法获取：
python -c "import serial.tools.list_ports;print [port for port in serial.tools.list_ports.comports() if port[2] != 'n/a']"
因为获取的列表里可能有“假冒”的，所以，上面的代码还检查了设备的 hwid。comports() 返回的是一个 list，元素是一个对象，查看其 type() 结果如下 ：
type(port)
class 'serial.tools.list_ports_linux.SysFS'
查看文档 pydoc serial.tools.list_ports_linux.SysFS，上面的 port[2] 是这个 port 的 hwid，另外还有 port[0] 是串口名称，port[1]是 description 。