UART terminal

another_one

Hello!

I wrote program which transfer "big data"(file) and receive ASCII simbol
Now I need to receive alse ASCII strinigs and control carriedge return and feedback
To receive ASCII symbol I used timer and call read fuction by timer count release
And the problem is I don't know how to call read function to be able to receive all ASCII strings without their size depends and how to call read permamently without taking all processing time

Thanks in advance

another_one

@another_one
Sorry for what post, I was wrong in declaring the point of the question.
Now I can receive any size data strings from COM-port by using checking bytes available.
And this data I transfer to textEdit at all, but the result I see in some wrong format, - I see uncompleted, by new line, strings.
And I think it has two reason:

timer->start(10), - I use timer event to read data from qextserialport driver and that divides the string;
ui->textEdit->append(tr("%1").arg(stReadHex)), - This function adds new line.

Thus, I need to control new line adding or exclude string dividing.
Please help!

Christian Ehrlicher

@another_one said in UART terminal:

timer->start(10), - I use timer event to read data from qextserialport driver and that divides the string;

Don't use a timer but signals and slots.
And since it's a stream you will for sure get some data but not a complete line - it's up to you to bring the data to a desired format.

another_one

@Christian-Ehrlicher

Thank you for your replay !

Could you give me some example, please ?
I serached about what before, but didn't find any similar to my case.

Thanks!

Christian Ehrlicher

The QSerialPort documentation has a lot of examples on how to use the serial port: https://doc.qt.io/qt-5/qtserialport-examples.html

Using signals and slots is a basic Qt feature you should learn - otherwise you will not have fun with Qt!

another_one

@Christian-Ehrlicher
Thank you!

another_one

@another_one
With your help I have done UART receive via signal and clots:

connect(port, SIGNAL(readyRead()), this, SLOT(readData()));
void MIPS_monitor::readData()
{
    const QByteArray data = port->readAll();
    ui->textEdit->append(data);
}

But string dividing is still exist

JonB

@another_one
@Christian-Ehrlicher has already answered that "string dividing" (as you call it) is natural/possible/inevitable. The signals have no guarantee they will be emitted e.g. "one line at a time". That's how it works.

As he has said

And since it's a stream you will for sure get some data but not a complete line - it's up to you to bring the data to a desired format.

It is your job to write code to "aggregate" received data in a buffer if you might want to "join" the data received at multiple signals.

another_one

@JonB

Sorry I didnt understand
I checked data stream from external device and that is not devide transferring data
I thouught what qt driver will give receiced data as is but I has his job as results in the following format:


Pin # 4 LED ON

Pin # 3 
LED ON

Pin # 3 LED OFF

Pin # 4 LED OFF

Pin # 3 LED ON

Pin # 3 LED OFF

Pin # 4 LED ON

Pin # 3 LED ON

Pin # 3 LED OFF

Pin # 4 LED OFF

Pin # 3 LED ON

Pin # 3 LED OFF

Pin # 4 LED ON

Pin # 3 LED ON

Pin # 3 LED OFF

Pin 
# 4 LED OFF

Pin # 3 LED ON

Pin # 3
 LED OFF

Pin # 4 LED ON

Pin # 3 LED ON

Pin # 3 LED OFF

Is it normal?, do you want to say what?
And as I udenerstand you right I must buffer (I think what it has already buffered by qt driver)that data to format it ?

Thanks

JonB

@another_one said in UART terminal:

Pin # 3
LED ON

Take this as an example. We have explained that it can happen that device sends Pin #3 LED ON in a single write(). So no "divide" as you call it.

But it is possible that readAll() can receive this in multiple "chunks"/"divides". So It could arrive as 2 pieces to readAll(): first time it gets Pin # 3, second time it gets remaining LED ON. And that seems to be happening here.

Since QTextEdit::append(text) documents "Appends a new paragraph" you will end up with separate lines if you call append() twice, once for each "fragment" of the line. If you want it output on one line you will need to "join" partial lines like this, only call append() when you have (one or more) full lines.

another_one

@JonB

Thank you for your detailed explanation the reason of the problem!
But sorry again, I didn't understand what should I do (how can I call "only append()") to solve this problem?.

Thanks in advaunce!

JonB

@another_one
Build up a line (however they are terminated, carriage return or whatever) before calling QTextEdit:: append(). I would keep a class member variable for a buffer and each time realAll() returns anything append it into that buffer. When a line is complete add it to the text edit and remove from the buffer. That's what a buffer is.

another_one

@JonB

Thank you again! sorry, but can you give me some example please?

And why simplified() and trimmed() can not solve this problem(I tried)?
And I don't understand one more moment:
I receive data what can consits of \r\n and "Appends a new paragraph" gives another one \r\n.
How can I parse needest one in this case?

mpergand

@another_one said in UART terminal:

I checked data stream from external device and that is not devide transferring data

In this case, have a try with canReadline() and then readLine()
Should be easier ...

another_one

@mpergand

Thanks to all
Now I have found temporary descision based on insertPlainText of QTextEdit Class