Sorry for double posting last time, this is my first time using google
groups.
>> I wonder if you run the application that failing for you there is you
pipe that data to a file,
>> instead of to stdout, if you would be experiencing the same problem ?
The data loss problem also happens when the yes command is just repeating a
string over and over to stdout so I don't think the problem is python
related.
>> Why don't you humor me, and give that a try ?
I tried:
$ python3.6 ~/reusable/BBB_pressure_streamer.py > some_log_file.txt
When I view the log file I can't see any errors
>> Have you tried reducing the receive FIFO level?
I had not thought of that. Today I tried setting the Tx and Rx buffers to
1, 8 and 14 bytes. Data continued to be lost on all settings.
>> Suspect I'd start with
>> stty ixon ixoff -ixany
>> and ensure the other end is set for equivalent.
I tried:
root@beaglebone:~# stty --file=/dev/ttyGS0 ixon ixoff -ixany
root@beaglebone:~# stty --all
speed 9600 baud; rows 0; columns 0; line = 0;
intr = ^C; quit = ^\; erase = ^?; kill = ^U; eof = ^D; eol = <undef>;
eol2 = <undef>; swtch = <undef>; start = ^Q; stop = ^S; susp = ^Z;
rprnt = ^R;
werase = ^W; lnext = ^V; flush = ^O; min = 1; time = 0;
-parenb -parodd cs8 hupcl -cstopb cread clocal -crtscts
-ignbrk brkint -ignpar -parmrk -inpck -istrip -inlcr -igncr icrnl ixon
ixoff
-iuclc -ixany imaxbel -iutf8
opost -olcuc -ocrnl onlcr -onocr -onlret -ofill -ofdel nl0 cr0 tab0 bs0
vt0 ff0
isig icanon iexten echo echoe echok -echonl -noflsh -xcase -tostop
-echoprt
echoctl echoke
and I also turned on flow control on the python side at the same time but I
still got data loss.
>> Recommend you specify /which/ serial port
I was originally running stty while connected to the virtual serial port
but I forgot to mention that detail.
>> I can't duplicate your results as
>> debian@beaglebone:~$ python3.6 -c "while True: print(sum(i for i in
range(10000)))"
I previously installed python3.6 on all my boards. I should have given an
example that only depended on base Debian.
>> #flush input buffer (where did .read_all() come from?)
It is from
https://github.com/pyserial/pyserial/blob/master/serial/serialutil.py
I was using it to clear the serial buffer of all data. Calling
.reset_input_buffer() is better
>> OKAY -- THIS PRODUCED a drop-out 2574..2659
Thanks, it is nice to know that someone else can replicate the issue, it is
not just me doing something stupid.
>> For a stable system, I would recommend considering doing the data
transfer over a real hardware serial port
Today I purchased two connectors for the hardware serial pins from:
https://www.dfrobot.com/product-147.html
I will see if that helps.
>> You never have been specific about how many bits per second of data that
you have to move.
Today I measured the average data rate of my application to be 69,218
bytes/second.
>> This seems to me that you are indeed overflowing your buffer.
>> How or why I'm not sure, but if sending 6 characters all is fine,
>> and 7 characters does not transmit properly then obviously something is
wrong.
When I send:
x.write(b'yes "123456"\n')
I receive 8 bytes per line not 6 due to the addition of /r/n. I don't think
this is terribly important though
>> I'm suspecting you're not showing us all your code
My working repository is here:
https://github.com/DavidHowlett/BBB_fault_demo
A permanent link to the relevant commit is here:
https://github.com/DavidHowlett/BBB_fault_demo/blob/389785ec4e50af35fd78673d338063458da6be04/on_PC.py
There is not much to see in the repository but you are welcome to have a
look.
The only thing worth noting is I use python 3.6 on the PC side too.
>> Here you can see the source code of USB serial gadged driver
Thankyou
>> The easiest solution is to do a simple handshake
That is a good idea for avoiding data loss, the troublesome buffer would
never fill so there would be no data loss.
>> Why you want to use RS232, i would choose TCP ,UDP or WebServer
Personal preexisting skill set. I have been using serial connections for 4
years on multiple projects with multiple pieces of hardware. I wrongly
believed that it would be easy to just use serial again.
In the future I plan to use the hardware serial connection.
>
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