void usart_init(void)
{
/* Enable USART2 APB clock */
	RCC_APB2PeriphClock_Enable(RCC_APB2PERIPH_USART1, ENABLE);
	/* USART1 Pins configuration **************************************************/
	{
		/* Configure the GPIO ports */
		GPIO_InitPara  GPIO_InitStructure;

		/* Connect pin to Periph */
		GPIO_PinAFConfig(GPIOA , GPIO_PINSOURCE9, GPIO_AF_1);
		GPIO_PinAFConfig(GPIOA , GPIO_PINSOURCE10, GPIO_AF_1);

		/* Configure pins as AF pushpull */
		GPIO_InitStructure.GPIO_Pin     = GPIO_PIN_9 | GPIO_PIN_10;
		GPIO_InitStructure.GPIO_Mode    = GPIO_MODE_AF;
		GPIO_InitStructure.GPIO_Speed   = GPIO_SPEED_50MHZ;
		GPIO_InitStructure.GPIO_OType   = GPIO_OTYPE_PP;
		GPIO_InitStructure.GPIO_PuPd    = GPIO_PUPD_NOPULL;
		GPIO_Init(GPIOA , &GPIO_InitStructure);
	} //GPIO setting

		
	{
		USART_InitPara  USART_InitStructure;

		USART_DeInit(USART1);
		USART_InitStructure.USART_BRR =9600;
		USART_InitStructure.USART_WL                  = USART_WL_8B;
		USART_InitStructure.USART_STBits              = USART_STBITS_1;
		USART_InitStructure.USART_Parity              = USART_PARITY_RESET;
		USART_InitStructure.USART_HardwareFlowControl = USART_HARDWAREFLOWCONTROL_NONE;
		USART_InitStructure.USART_RxorTx              = USART_RXORTX_RX | USART_RXORTX_TX;
		USART_Init(USART1, &USART_InitStructure);
	} 
	{
		NVIC_InitPara  NVIC_InitStructure;

		/* Configure the NVIC Preemption Priority Bits */
		/* Configure the preemption priority and subpriority:
		   - 1 bits for pre-emption priority: possible value are 0 or 1
		   - 3 bits for subpriority: possible value are 0..7
		   - Lower values gives higher priority
		 */

		/* Re-configure and enable USART interrupt to have the higher priority */
		NVIC_InitStructure.NVIC_IRQ						= USART1_IRQn;
		NVIC_InitStructure.NVIC_IRQPreemptPriority		= 5;
		NVIC_InitStructure.NVIC_IRQSubPriority			= 1;
		NVIC_InitStructure.NVIC_IRQEnable				= ENABLE;
		NVIC_Init(&NVIC_InitStructure);
	} //NVIC  usart2 setting
	/* Enable the USART1 Receive interrupt */
	USART_INT_Set(USART1, USART_INT_RBNE, ENABLE);
	/* USART enable */
	USART_Enable(USART1, ENABLE);
	
}
 

//傳送單位元組
void usart_transmit( unsigned char data )
{
 USART_ClearBitState (USART1,USART_FLAG_TC);
 USART_DataSend(USART1,data);
 while(USART_GetBitState(USART1,USART_FLAG_TC)==RESET);
 USART_ClearBitState (USART1,USART_FLAG_TC);
}

//傳送字串
void usart_send_string(char *str)
{
 while(*str)
 {
 usart_transmit(*str) ;
 str++;
 }
}