Serial port split data

[Lesiok]

And these packages do not have any fixed structure? If so, the protocol is incorrectly designed.

[ado130]

Of course not, these packages have fixed structure. I have just 3 or 4 different patterns.

[oazive]

I had the same Problem few days ago,
try to add special characters like crlf and append your data on a QString (or anything you want) until you recieve crlf.
QSerialPort doesn't know your frame so it only recieve data when it is available.

[ado130]

Yes, it is possible way to solve this problem. But I can't be sure that this special character will not be part of correct data - packet and I think, in 21th century is possible to transfer all data without any special characters at the end. I'm just saying, when I sent 20B I also get 20B. So, I changed my program to check this length and it seems working correctly.

[scgrant327]

Yes, it is possible way to solve this problem. But I can't be sure that this special character will not be part of correct data - packet and I think, in 21th century is possible to transfer all data without any special characters at the end. I'm just saying, when I sent 20B I also get 20B. So, I changed my program to check this length and it seems working correctly.

In any century, it is not possible to just 'transfer all data' via a serial port without some way to verify the data on the receiving end. The way you are doing WILL fail at some point. If your do not have a starting element or an ending element (preferably both), you can never be absolutely 100% sure you have the correct data.

My advice is if you truly know the structure of the 3 or 4 patterns like you mentioned above, then you should implement code to check the received data fits into one of those patterns.

If something should happen during transmission, and a byte is dropped... or part of the packet is corrupted, then your data will be wrong...and assuming that just because you received 20 bytes that the data is good... is a very, very bad idea.

Just my 2 cents...