Re: Problems with serial port interface
I've some other informations:
i've created a class like this
class CReader(QThread):
def start(self, ser, priority = QThread.InheritPriority):
self.ser = ser
QThread.start(self, priority)
self._isRunning = True
self.numData=0;
def run(self):
print("Enter Creader")
while True:
if self._isRunning:
try:
data = self.ser.read(self.numData)
n = self.ser.inWaiting()
if n:
data = self.ser.read(n)
print(data)
except:
errMsg = "Reader thread is terminated unexpectedly."
self.emit(SIGNAL("error(QString)"), errMsg)
else:
return
def stop(self):
self._isRunning = False
self.wait()
I've tested my class and it works well and i have no error messages.
So, i think that my problem is this line (taken from previous code)
self.emit(SIGNAL("newData(QString)"), data.decode('cp1252', 'ignore'))
i need this line to display all data received to my QT interface, so can't be
removed.
I've tried to use a timer to display data every 500ms: my program crasches
after 5minutes.
Can you help me?
Thanks
--
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Re: Problems with serial port interface
I've done some tests: i've simulated a serial transmission with 1. Terminal.exe https://sites.google.com/site/terminalbpp/ 2. Com0com I've made a script that transmit a char every 5ms. The test system is Terminal---Com0Com---Terminal so i haven't used my program. After 3-4minutes the terminal program crashes, so i think that i have an OS problem: what do you think?I'm using Windows7/64bit... Any suggestion? Thanks -- http://mail.python.org/mailman/listinfo/python-list
Re: Problems with serial port interface
Ok, thanks for your reply. But i have another problem: i hadn't always the hardware needed for the tests. Before i've used a terminal and com0com to simulate a serial input: if i want to simulate a transmission every 5ms how can i do? I need a program or a code that i'm sure about its correctness. Another question: may i have some problems (for example timings) to simulate with the same pc a serial transmission? Any suggestion? Thanks -- http://mail.python.org/mailman/listinfo/python-list
Re: Problems with serial port interface
On 07/06/2013 11:17, lionelgreenstr...@gmail.com wrote:
Sorry for my quote,
but do you have any suggestion?
Il giorno martedì 4 giugno 2013 23:25:21 UTC+2, lionelgr...@gmail.com ha
scritto:
Hi,
i'm programming in python for the first time: i want to create a serial port
reader. I'm using python3.3 and pyQT4; i'm using also pyserial.
Below a snippet of the code:
class CReader(QThread):
def start(self, ser, priority = QThread.InheritPriority):
self.ser = ser
QThread.start(self, priority)
self._isRunning = True
self.numData=0;
def run(self):
print("Enter Creader")
while True:
if self._isRunning:
try:
data = self.ser.read(self.numData)
n = self.ser.inWaiting()
if n:
data = self.ser.read(n)
self.emit(SIGNAL("newData(QString)"),
data.decode('cp1252', 'ignore'))
self.ser.flushInput()
except:
pass
else:
return
def stop(self):
self._isRunning = False
self.wait()
This code seems work well, but i have problems in this test case:
+baud rate:19200
+8/n/1
+data transmitted: 1 byte every 5ms
After 30seconds (more or less) the program crashes: seems a buffer problem, but
i'm not really sure.
What's wrong?
Using a "bare except" like this:
try:
...
except:
...
is virtually always a bad idea. The only time I'd ever do that would
be, say, to catch something, print a message, and then re-raise it:
try:
...
except:
print("Something went wrong!")
raise
Even then, catching Exception would be better than a bare except. A
bare except will catch _every_ exception, including NameError (which
would mean that it can't find a name, possibly due to a spelling error).
A bare except with pass, like you have, is _never_ a good idea. Python
might be trying to complain about a problem, but you're preventing it
from doing so.
Try removing the try...except: pass and let Python tell you if it has a
problem.
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Re: Problems with serial port interface
lionelgreenstr...@gmail.com wrote:
> Sorry for my quote,
> but do you have any suggestion?
>> After 30seconds (more or less) the program crashes: seems a buffer
>> problem, but i'm not really sure.
>>
>> What's wrong?
I don't use qt or pyserial myself, but your problem description is too vague
anyway. Some random remarks:
Does your script segfault or do you get a traceback? If the latter, post it.
As you are using two external libraries, can you limit the problem to a
single one? For example: temporarily replace pyserial with a file. Do the
problems persist?
What happens if you remove the bare
try: ...
except: pass
? It may hide useful information.
Finally, can you make a self-contained example that we can run? Make it as
simple as possible. I'd start with something like
class CReader(QThread):
def __init__(self, ser):
self.ser = ser
def run(self):
while True:
data = self.ser.read(1)
if data:
n = self.ser.inWaiting()
if n:
data += self.ser.read(n)
text = data.decode('cp1252', 'ignore')
print(text)
# adding the following would be the next step
#self.emit(SIGNAL("newData(QString)"), text)
and once you have something that does run you can gradually increase
complexity until it breaks.
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Re: Problems with serial port interface
Sorry for my quote,
but do you have any suggestion?
Il giorno martedì 4 giugno 2013 23:25:21 UTC+2, lionelgr...@gmail.com ha
scritto:
> Hi,
>
> i'm programming in python for the first time: i want to create a serial port
> reader. I'm using python3.3 and pyQT4; i'm using also pyserial.
>
> Below a snippet of the code:
>
>
>
> class CReader(QThread):
>
> def start(self, ser, priority = QThread.InheritPriority):
>
> self.ser = ser
>
> QThread.start(self, priority)
>
> self._isRunning = True
>
> self.numData=0;
>
>
>
> def run(self):
>
> print("Enter Creader")
>
> while True:
>
> if self._isRunning:
>
> try:
>
> data = self.ser.read(self.numData)
>
> n = self.ser.inWaiting()
>
> if n:
>
> data = self.ser.read(n)
>
> self.emit(SIGNAL("newData(QString)"),
> data.decode('cp1252', 'ignore'))
>
> self.ser.flushInput()
>
> except:
>
> pass
>
> else:
>
> return
>
>
>
> def stop(self):
>
> self._isRunning = False
>
> self.wait()
>
>
>
> This code seems work well, but i have problems in this test case:
>
>
>
> +baud rate:19200
>
> +8/n/1
>
> +data transmitted: 1 byte every 5ms
>
>
>
> After 30seconds (more or less) the program crashes: seems a buffer problem,
> but i'm not really sure.
>
> What's wrong?
>
> Thanks
--
http://mail.python.org/mailman/listinfo/python-list
Problems with serial port interface
Hi,
i'm programming in python for the first time: i want to create a serial port
reader. I'm using python3.3 and pyQT4; i'm using also pyserial.
Below a snippet of the code:
class CReader(QThread):
def start(self, ser, priority = QThread.InheritPriority):
self.ser = ser
QThread.start(self, priority)
self._isRunning = True
self.numData=0;
def run(self):
print("Enter Creader")
while True:
if self._isRunning:
try:
data = self.ser.read(self.numData)
n = self.ser.inWaiting()
if n:
data = self.ser.read(n)
self.emit(SIGNAL("newData(QString)"),
data.decode('cp1252', 'ignore'))
self.ser.flushInput()
except:
pass
else:
return
def stop(self):
self._isRunning = False
self.wait()
This code seems work well, but i have problems in this test case:
+baud rate:19200
+8/n/1
+data transmitted: 1 byte every 5ms
After 30seconds (more or less) the program crashes: seems a buffer problem, but
i'm not really sure.
What's wrong?
Thanks
--
http://mail.python.org/mailman/listinfo/python-list
