QSerialPort - readAll stops after CR

[hkottmann]

Dear all

If I read from serial port using readAll it stops after receiving a CR (\r). Device Monitoring Studio reads the following string:

24 30 37 37 0D 24 30 37 37 0D $077.$077.

requestData.append(cormet->readLine());
cormet->clear();
qDebug() << "All " << requestData;

The qDebug() output is as follows:

All "$077\r"
All "$077\r"

What can I do that the whole buffer is read without taking notice CR or LF since also data in binary (Modbus) format are transferred here (I have afterwards to determine the data format).

Thanks in advance.

Hans

[ollarch]

@hkottmann You are calling "readLine()" that just stops reading when find a CR.

[hkottmann]

I've just tried this too. But this here does the same:

requestData.append(cormet->readAll());
cormet->clear();
qDebug() << "All " << requestData;

All "$077\r"
All "$077\r"

Kind regards,

Hans

[JonB]

@hkottmann
readAll() does not "stop" after reading a \r or anything else. Review where you are calling this from (i.e. needs to be readyRead() signal/slot). You must allow for received data arriving in multiple "chunks", regardless of how they might have been sent.

[ollarch]

@hkottmann as @JonB points, you have to add the recived data to a buffer and parse it. As you are receiving Modbus responses, the protocol tells you how to calculate how long the response will be, so you know how many bytes are you expecting.