[英]How to write on serial port in python that ttyUSB0 will be interpreted commands?
I have raspberry PI B+ with connected Telegesis ZigBee module(ETRX3 USB sticks) via USB. 我有覆盆子PI B +通过USB连接Telegesis ZigBee模块(ETRX3 USB记忆棒)。 Using commands: 使用命令:
debian:~# stty -F /dev/ttyUSB0 -raw ispeed 19200 ospeed 19200
debian:~# cat < /dev/ttyUSB0 &
debian:~# echo "ATI" > /dev/ttyUSB0
the ZigBee module executed ATI command and I can see the correct output: ZigBee模块执行ATI命令,我可以看到正确的输出:
Telegesis ETRX357
R308C
OK
The same thing I want to do with python script. 我想用python脚本做同样的事情。 I was written python script with code: 我写了python脚本代码:
#!/usr/bin/env python
# based on tutorials:
# http://www.roman10.net/serial-port-communication-in-python/
# http://www.brettdangerfield.com/post/raspberrypi_tempature_monitor_project/
import serial, time
SERIALPORT = "/dev/ttyUSB0"
BAUDRATE = 19200
ser = serial.Serial(SERIALPORT, BAUDRATE)
ser.bytesize = serial.EIGHTBITS #number of bits per bytes
ser.parity = serial.PARITY_NONE #set parity check: no parity
ser.stopbits = serial.STOPBITS_ONE #number of stop bits
#ser.timeout = None #block read
#ser.timeout = 0 #non-block read
ser.timeout = 2 #timeout block read
ser.xonxoff = False #disable software flow control
ser.rtscts = False #disable hardware (RTS/CTS) flow control
ser.dsrdtr = False #disable hardware (DSR/DTR) flow control
ser.writeTimeout = 0 #timeout for write
print 'Starting Up Serial Monitor'
try:
ser.open()
except Exception, e:
print "error open serial port: " + str(e)
exit()
if ser.isOpen():
try:
ser.flushInput() #flush input buffer, discarding all its contents
ser.flushOutput()#flush output buffer, aborting current output
ser.write("ATI")
print("write data: ATI")
time.sleep(0.5)
numberOfLine = 0
while True:
response = ser.readline()
print("read data: " + response)
numberOfLine = numberOfLine + 1
if (numberOfLine >= 5):
break
ser.close()
except Exception, e:
print "error communicating...: " + str(e)
else:
print "cannot open serial port "
and get results as on the screen 并在屏幕上获得结果
ATI
but I want to command be execute by ZigBee module, as like in shell commands. 但我希望命令由ZigBee模块执行,就像在shell命令中一样。 What am I doing wrong? 我究竟做错了什么?
you need to append an end-of-line to your write() 你需要在你的写()附加一行结尾
ser.write("ATI\\r\\n")
you should change the timeout to: 你应该将超时更改为:
ser.timeout = None
Otherwise readline() will return after 2 seconds, even if nothing has been read. 否则readline()将在2秒后返回,即使没有读取任何内容。
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