STM32F769I DISCOVERY problem in debugging using uart

Hi community,

I'm using stm32f769i discovery, I communicate with Vacuum Transducer via the uart protocol.

Once I receive the whole data send by  the vacuum Transducer  to the stm ( @253ACK9.00E+2FF ) and that I stocked in a reception buffer ,I use a variable pression to write just the bit(7,12,13) who refer to the pression value. and then print the pression.

In the debug mode my code execute only the two lignes of (transmission and reception), so I can't get the pression value and even I can't get the data stocked in buffrec, it 's as if I lose the data in buffrec. If I remove all lines after 

HAL_UART_Receive_IT(&UartHandle, buffrec , 17) I can find data in buffrec.

Here is my code:

uint8_t bufftr[30] = '@253PR1?;FF';

uint8_t buffrec[17];

double pression;

while (1)

HAL_UART_Transmit_IT(&UartHandle, bufftr, 30);

@253ACK9.00E+2FF;

if(inputBuffer2[12] == 43)

{

pression = (inputBuffer2[7]-48)*pow(10,(inputBuffer2[13]-48));

}

pression = (inputBuffer2[7]-48)*pow(10,-(inputBuffer2[13]-48));

}

printf('%lf%,pression);

}

Can anyone help me to know what I'm missing?

thanks in advance