Number of bytes receives not the same after each cycle

[AUDI_ENG]

Hi,

I want to receive 9 bytes after each cycle
Im using the QSerialPort to comunicate between a reaspberry pi and an other device (microcontroller)

I write a code

I have perfectly 9 bytes after each cycle but not in the same QbyteArray :

for example :

nb data read = 9 bytes = "011109101809090913"
nb data read = 8 bytes = "0209091018090909"
nb data read = 1 bytes = "13"
nb data read = 8 bytes = "0309091018090908"
nb data read = 1 bytes = "13"
nb data read = 9 bytes = "04110910170909090f"
nb data read = 9 bytes = "050909101809090913"
nb data read = 9 bytes = "061509101809090813"
nb data read = 8 bytes = "0711091018080909"
nb data read = 10 bytes = "1308110910170908090f"

I want to receive exaclty 9 bytes :

If u see the example , you can remark that each byte have an ID(1,2,3....) and 8 other bytes
and when i have 8 bytes, the next byte is the end of the later (8 bytes) ..

i have this code

StopAff->setEnabled(true);
  QByteArray bytes;
  bytes = PortReception->readAll();
  qDebug() <<"nb data read = " << bytes.size() << "   bytes = "<< bytes.toHex();

StopAff->setEnabled(true);
  QByteArray bytes;
  bytes = PortReception->readAll();
  qDebug() <<"nb data read = " << bytes.size() << "   bytes = "<< bytes.toHex();

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How I can resolve the problem