I want to write a simple code in python to send USSD codes to a GSM modem (D-link DWM-157) and receive their results and store them in variables. I can connect to the modem with minicom and also miniterm.py. But the problem is that they need a terminal to send/receive AT commands to the modem. I don't want an extra terminal. I also use the following code to send a simple AT command but when I run the code nothing happens:
import serial, time
def serial_def():
ser = serial.Serial()
ser.port = "/dev/ttyUSB2"
ser.baudrate = 115200
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 = 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 = 2
ser.open()
if ser.isOpen():
print(ser.name + ' is open...')
ser.write("AT"+"\r\n")
time.sleep(1)
out=''
while True:
out += ser.read(1)
print (out)
ser.close()
if __name__ == '__main__':
serial_def()
When I run the code I only see the following:
/dev/ttyUSB2 is open...
Any help is appreciated.
Related
I am trying to use a python script to control a rotating valve. I am able to do so through PuTTY but not using my script. Code is shown below. I also included PuTTY settings and a link to the valve positioner user manual that gives example commands.
import serial
ser = serial.Serial()
ser.port = 'COM7'
ser.baudrate = 9600
ser.bytesize = serial.SEVENBITS
ser.parity = serial.PARITY_ODD
ser.xonxoff = 0
ser.rtscts = 0
ser.dsrdtr = 0
ser.stopbits = 1
ser.timeout = 1
ser.open()
if ser.isOpen():
print(ser.name + ' is open...')
while True:
cmd = input("Enter command or 'exit':")
if cmd == 'exit':
ser.close()
break
else:
# ser.write(cmd.encode('ascii'))
# ser.write(bytes(cmd, 'utf-8'))
ser.write(str.encode(cmd))
out = ser.readline()
print('Receiving... ' + str(out))
The manual that you link to says that it needs a <CR> at the end of each command.
Also your putty configuration says that it adds crlf.
You could change your code like this:
ser.write(str.encode(cmd + '\r\n'))
I'm still new in python so please bear with me, so I'm trying to write a script with python2-pyserial but I keep getting error Attempting to use a port that is not open Here's the script:
#!/usr/bin/python
import serial, time
#initialization and open the port
#possible timeout values:
# 1. None: wait forever, block call
# 2. 0: non-blocking mode, return immediately
# 3. x, x is bigger than 0, float allowed, timeout block call
ser = serial.Serial()
ser.port = "/dev/ttyUSB2"
ser.baudrate = 115200
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 = 1 #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 = 2 #timeout for write
try:
ser.open()
print ("Port has been opened")
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()
ser.write("ATI")
print("write data: ATI")
time.sleep(1) #give the serial port sometime to receive the data
numOfLines = 0
while True:
response = ser.readline()
print("read data: " + response)
numOfLines = numOfLines + 1
if (numOfLines >= 5):
break
#pass
ser.close()
except Exception, e1:
print ("error communicating...: ") + str(e1)
else:
print ("cannot open serial port ")
I've tried to run the script with sudo python2 ser but I still have the same error. How do I fix it ?
The first part of your code is wrong, you're making the wrong attributions for ser. Try the following way:
ser = serial.Serial(
port = "/dev/ttyUSB2",
baudrate = 115200,
bytesize = serial.EIGHTBITS,
parity = serial.PARITY_NONE,
stopbits = serial.STOPBITS_ONE,
timeout = 1,
xonxoff = False,
rtscts = False,
dsrdtr = False,
writeTimeout = 2
)
On my environment, the port was already open after that, but if it isn't you can try to open it:
ser.open()
ser.isOpen()
And you have to be sure that this is not a virtual port on your pc if it is, you will have to change this:
ser.rtscts = False #disable hardware (RTS/CTS) flow control
ser.dsrdtr = False #disable hardware (DSR/DTR) flow control
For this:
ser.rtscts = True
ser.dsrdtr = True
Check out this issue for more info
I'm trying communicate with STM32L152RB board through COM port 4 which accepts commands from COM4 and displays result in terminal using this code but it's not working ... I'm new to python please let me know what I'm doing wrong.
#Global Variables
ser = 0
def init_serial():
COMNUM = 4 #Enter Your COM Port Number Here.
global ser #Must be declared in Each Function
ser = serial.Serial()
ser.baudrate = 9600
ser.port = COMNUM - 1 #COM Port Name Start from 0
#ser.port = '/dev/ttyUSB0' #If Using Linux
#Specify the TimeOut in seconds, so that SerialPort
#Doesn't hangs
ser.timeout = 10
ser.open() #Opens SerialPort
# print port open or closed
if ser.isOpen():
print 'dis' + ser.portstr
init_serial()
temp = raw_input('Type what you want to send, hit enter:\r\n')
ser.write('dis') #Writes to the SerialPort
while 1:
bytes = ser.read() #Read from Serial Port
print 'You sent: ' + bytes #Print What is Read from Port
I have raspberry PI B+ with connected Telegesis ZigBee module(ETRX3 USB sticks) via USB. Using commands:
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:
Telegesis ETRX357
R308C
OK
The same thing I want to do with python script. I was written python script with code:
#!/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
ATI
but I want to command be execute by ZigBee module, as like in shell commands. What am I doing wrong?
you need to append an end-of-line to your write()
ser.write("ATI\r\n")
you should change the timeout to:
ser.timeout = None
Otherwise readline() will return after 2 seconds, even if nothing has been read.
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Can someone please show me a full python sample code that uses pyserial, i have the package and am wondering how to send the AT commands and read them back!
Blog post Serial RS232 connections in Python
import time
import serial
# configure the serial connections (the parameters differs on the device you are connecting to)
ser = serial.Serial(
port='/dev/ttyUSB1',
baudrate=9600,
parity=serial.PARITY_ODD,
stopbits=serial.STOPBITS_TWO,
bytesize=serial.SEVENBITS
)
ser.isOpen()
print 'Enter your commands below.\r\nInsert "exit" to leave the application.'
input=1
while 1 :
# get keyboard input
input = raw_input(">> ")
# Python 3 users
# input = input(">> ")
if input == 'exit':
ser.close()
exit()
else:
# send the character to the device
# (note that I happend a \r\n carriage return and line feed to the characters - this is requested by my device)
ser.write(input + '\r\n')
out = ''
# let's wait one second before reading output (let's give device time to answer)
time.sleep(1)
while ser.inWaiting() > 0:
out += ser.read(1)
if out != '':
print ">>" + out
import serial
ser = serial.Serial(0) # open first serial port
print ser.portstr # check which port was really used
ser.write("hello") # write a string
ser.close() # close port
use https://pythonhosted.org/pyserial/ for more examples
http://web.archive.org/web/20131107050923/http://www.roman10.net/serial-port-communication-in-python/comment-page-1/
#!/usr/bin/python
import serial, time
#initialization and open the port
#possible timeout values:
# 1. None: wait forever, block call
# 2. 0: non-blocking mode, return immediately
# 3. x, x is bigger than 0, float allowed, timeout block call
ser = serial.Serial()
#ser.port = "/dev/ttyUSB0"
ser.port = "/dev/ttyUSB7"
#ser.port = "/dev/ttyS2"
ser.baudrate = 9600
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 = 1 #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 = 2 #timeout for write
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
#and discard all that is in buffer
#write data
ser.write("AT+CSQ")
print("write data: AT+CSQ")
time.sleep(0.5) #give the serial port sometime to receive the data
numOfLines = 0
while True:
response = ser.readline()
print("read data: " + response)
numOfLines = numOfLines + 1
if (numOfLines >= 5):
break
ser.close()
except Exception, e1:
print "error communicating...: " + str(e1)
else:
print "cannot open serial port "
I have not used pyserial but based on the API documentation at https://pyserial.readthedocs.io/en/latest/shortintro.html it seems like a very nice interface. It might be worth double-checking the specification for AT commands of the device/radio/whatever you are dealing with.
Specifically, some require some period of silence before and/or after the AT command for it to enter into command mode. I have encountered some which do not like reads of the response without some delay first.