int fputcint ch FILE f usart_data_transmitBL_USART uint8_t ch; whileRESET == usart_flag_getBL_USART USART_FLAG_TBE; return ch;

This function writes a character to a file. It uses the usart_data_transmit function to transmit the character over USART. It then waits for the transmission to complete by checking the USART_FLAG_TBE flag. Finally, it returns the character that was written.