DSPS hardware flow control

Hi guys.
I try to sand characters from an ATXMEGA microcontroller to DSPS android app through DA14580. The number of character sand are right but the problem is that not all of they are right.
My program sand 10 "r" but the DSPS app receive "r" (that in ASCII is decode as 0x72) and another character that in ASCII are decode as 0xb2.
I try to implement the hardware flow control inside the ATXMEGA instead short-circuit CTS e RTS of BT module, but the result don't change..
I implement the hardware flow control for ATXMEGA in this way:
首先我将RTS销设置为1,比我等待一个0in the CTS pin and last I use the usart send function that first control for empty usart buffer than write in buffer.
Before, I tried the DSPS profile, connecting the DA14580 basic-DEVKIT to the PC through an RS232, but in this way it works fine.
I don't know if the problem is a synchronization issue between ATXMEGA and DA14580 (that shoud not exist with hardware flow control, I think) or my hardware flow control implementation.