I am having trouble connecting to a data acquisition box using a python3 script through a USB serial port. The box expects to receive an Enter Key to start responding and to get a username and password.
I have tried the following code to send the Enter key but I never receive anything from the serial port. Using a Terminal Emulator, it works just fine and after pressing enter I see the prompt waiting to log in.
import serial
ser = serial.Serial('COM5', 115200)
ser.write(str.encode('\r'))
ser.write(str.encode('\n'))
ser.writelines(str.encode('\r'))
ser.writelines(str.encode('\r\n'))
ser.write(bytes("\r",encoding='ascii'))
while True:
s = ser.readline()
print(s.decode('utf-8'))
Could someone kindly help?
Related
I have a terminal which I connect to with serial communication, and I want to read from it and write to it some commands I prepared in advance in a string array
Using pySerial, I need to write a code that will read the lines with a stop condition which is a wait from the console for input from the user, and then write the commands from the array
Just want to clarify, it's like an automatic PuTTY, and no I can't connect to the terminal through ssh, and no I can't bood the machine's terminal since it's not a pc
here is what i tried:
import serial
Baud_Rate = 9600
Ser = serial.Serial('COM4', Baud_Rate)
while Ser.isOpen():
input('Error: Ser is already open, please close it manually. if the port is
closed, press enter\n')
try:
Ser.close()
except serial.serialutil.PortNotOpenError:
pass
Ser.open()
Serial_com = [] #a str array with the relevant commands
for i in range(len(Serial_com)):
ter = Ser.readline()
while ter != 0xaf:
#print(str(ter))
print(str(ter.decode('utf-8').rstrip('\r\n')))
ter = Ser.readline()
sleep(1)
if i == 0:
print('login: root')
Ser.write(bytes("root", encoding='utf-8'))
else:
print('\n\n\n\n\nroot # Ser: ~ # ' + str(Serial_com[i]))
Ser.write(bytes(Serial_com[i], encoding='utf8'))
I realized that once the serial port is waiting for the python code (or the user) to write commands, that it sends the character 0xaf. It might be a coincidence, but still I wrote that as a stop condition for the reading from the terminal
the code can read from the serial port, but once it needs to write to the serial port it won't proceed
I can't share the rest because it's confedencial for a project
(update)
So I found some documentation on this link
https://elinux.org/RPi_Serial_Connection#Connections_and_signal_levels
If you scroll down you will find a section "S/W: Preventing Linux from using the serial port" It says "By default Linux will grab the serial port and use it as a terminal."
So it appears that this is a thing, however, the instructions it gives is for a Raspberry Pi, and it calls for you to use raspi-config. It doesn't give anything for regular linux use.
Using python I'm attempting to communicate between my laptop and an Up-Board. I'm connecting the Up-board by using an FTDI cable, connected to the serial connection on the board.
(OP)
I've done something similar before with C++ on a different board. The code I'm using I pulled from this site, http://www.varesano.net/blog/fabio/serial%20rs232%20connections%20python
import time
import serial
ser = serial.Serial(
port='/dev/ttyUSB0',
baudrate=115200,
parity=serial.PARITY_NONE,
stopbits=serial.STOPBITS_ONE,
bytesize=serial.EIGHTBITS
)
print ser.isOpen()
input=1
while 1 :
input = raw_input(">> ")
print "Check"
try:
if input == 'exit':
ser.close()
exit()
else:
ser.write(input + '\r\n')
out = ''
time.sleep(1)
while ser.inWaiting() > 0:
out += ser.read(1)
if out != '':
print ">>" + out
except:
ser.close()
break
I'm doing something similar on the Up-board. The only difference is that it waits for a message, then returns the message back to my laptop. Just a loop back between the Upboard and my laptop.
Here's where it gets interest.
I'm having two seperate issues.
1) I'll attempt to send a word, ie "test" and it will only send "e", "tst" doesn't get sent
2) The other issue is, it sends message, and I get a return for a password. So I reset the software and attempt to connect again, this time I send the username as the first message. I get back a reply for password, then I send the password, and now I have terminal access to the Upboard. While, all I really want is to connect to the application on the other end.
Does anyone have any suggestions on what is going on?
So I found the resolution, it appears that the system was configured in grub to connect to terminal on the same port address.
if you go to /etc/default/grub you will find a line
GRUB_CMDLINE_LINUX="console=ttyS0, 115200n8"
I ended up commenting that line, and I now can connect without it giving me console control.
I am trying to open a serial port connection and keep it open as long as data if communicating. I also want to respond if certain data is received. Below is an example of the python script. I am able to open the serial port send data and the script responds, it will not respond with the elif data.
I am new to pyserial and have been working on python lately but not great by any means.
Thank you
import serial
import time
ser = serial.Serial('/dev/ttyUSB0', timeout=10) # open serial port
print(ser.name) # check which port was really used
response = ser.read()
if response == (b'\r'):
ser.write (b'ID=')
elif response == (b'\r\r\x1bPG1\r'):
ser.write (b'110 1.8<CR><ACK><CR><ESC>[p<CR>')
#time.sleep(5)
#print ()
#ser.close() # close port
Hi please bear my basic question as I am new to python.
I am trying to read data from serial port. Basically serial port is a USB port converted to serial port virtually. I am using arduino.
First i tried this code:
while(True):
ser=serial.Serial('COM6',9600)
bytoread=ser.inWaiting()
val=ser.read(bytoread)
But it gave me error.
Permission Error(13,Access is denied, none 5)
But when i changed my code to
while(True):
ser=serial.Serial()
ser.baudrate=19600
ser.port='COM6'
ser
ser.open()
bytoread=ser.inWaiting()
val=ser.read(bytoread)
Permission error did not come but program is always busy connecting the port. I waited for many minutes but it never moved forward. What I am doing wrong here?
you can do something like :
import serial
ser = serial.Serial('COM6', 9600, timeout=None)
while True:
data = ser.readline()
you can't put ser = serial.Serial('COM5', 9600, timeout=None) in your while loop because it will permanently (re)create the connection...
import time
import serial
# configure the serial connections (the parameters differs on the device you are connecting to)
ser = serial.Serial(
port='/dev/ttyS0',
#port='/dev/ttyACM0',
baudrate=115200,
parity=serial.PARITY_ODD,
#stopbits=serial.STOPBITS_TWO,
#bytesize=serial.SEVENBITS
)
ser.isOpen() # returns true
time.sleep(1);
ser.write("some_command \n")
ser.close()
I have a embedded board. It has a serial port which is connected to my computer. I am running above script to access this serial port and run some board specific commands.
My problem
I open my serial port (using minicom in linux) separately and then run above script, It works. If I don't open serial port separately, Script doesn't work.
try
ser.write("some_command \n".encode())
alternatively try
ser.write(bytes(b"some_command \n"))