Serial port issue

[va3su]

I have a simple serial port program that works perfectly when I run it from a remote serial login from my pc (putty). (not Ethernet). The pc is connected via a ftdi serial to 3.3V usb adapter. All good. But the problem is when I run the same program from the Python Shell running in the Dabian gui, the Python shell gives me an error:

Python 3.4.2 (default, Oct 19 2014, 13:31:11)
[GCC 4.9.1] on linux
Type "copyright", "credits" or "license()" for more information.
>>> ================================ RESTART ================================
>>>
Traceback (most recent call last):
File "/home/pi/my_python/my.py", line 7, in <module>
rcv = port.read(1)
File "/usr/lib/python3/dist-packages/serial/serialposix.py", line 460, in read
raise SerialException('device reports readiness to read but returned no data (device disconnected?)')
serial.serialutil.SerialException: device reports readiness to read but returned no data (device disconnected?)
>>>

Thanks for any help.

[paddyg]

does is make any difference if you open the terminal as su?

[va3su]

Below is a simple program that "works" under certain conditions on a RPi3. The Pi3 has updated Debian so all the initial Pi3 serial port issues have been cleared up. First of all it works perfectly when I launch the python code from a Putty serial connection from my pc( using a serial to usb adapter) . This is ok but for the final application I will not be able to launch the program from the serial connection, I want to do it from a hdmi touch screen that I have. I also need to see the serial comms on the screen. I feel that the port command is the problem but don't know how to fix it.

Also... how do I setup up a exit program command? The amount of misinformation on this topic is epic.

Regards,
Kevin

import serial

port = serial.Serial("/dev/serial0", baudrate=115200, timeout=1.0)

while True:
rcv = port.read(1)
port.write(rcv)
if (rcv == "a"):
port.write("aaa")
if (rcv == "b"):
port.write("bbb")
if (rcv == "c"):
port.write("ccc")
if (rcv == "x"):
break

[va3su]

... the tabs are correct in my code... the forum seams to hate white space.

[SonOfAMotherlessGoat]

The forum expects you to put in some effort first (Hint: Use Code tags):

viewtopic.php?f=32&t=84477

[DougieLawson]

The forum expects you to put in some effort first (Hint: Use Code tags):

viewtopic.php?f=32&t=84477

Except that post doesn't explain the markup needed to activate "code tags".

If code-tags == "not used":
print "not formatted"
else:
print "formatted nicely"

Wrapped in [code]If code-tags == "not used":
print "not formatted"
else:
print "formatted nicely"[/code] tags it becomes

Code: Select all

If code-tags == "not used":
  print "not formatted"
else:
  print "formatted nicely"

[va3su]

Well, here's my bit of python and I seam to have sorted the formatting for this forum... Original problem remains however.

Code: Select all

import serial



port = serial.Serial("/dev/serial0", baudrate=115200, timeout=1.0)

while True:
   # port.write("\r\nSay something:")
	rcv = port.read(1)
	port.write(rcv)
	if (rcv == "a"):
		port.write("aaa")
	if (rcv == "b"):
		port.write("bbb")
	if (rcv == "c"):
		port.write("ccc")
	if (rcv == "x"):
		break

quit