#include "Usart.h"

void Usart_Init(void)
{
	USART_InitTypeDef USART_InitStructure;
    GPIO_InitTypeDef GPIO_InitStructure;
	
	/* Enable GPIO clock */
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_AFIO, ENABLE);
	/* Enable USART clock */
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE);
	
	/* Configure USART Tx as alternate function push-pull */
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_InitStructure.GPIO_Pin = USART_TX_pin;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(USART_GPIO, &GPIO_InitStructure);

    /* Configure USART Rx as input floating */
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
    GPIO_InitStructure.GPIO_Pin = USART_RX_pin;
    GPIO_Init(USART_GPIO, &GPIO_InitStructure);

    /* USARTx configured as follow:
    	  - BaudRate = 115200 baud
    	  - Word Length = 8 Bits
    	  - One Stop Bit
    	  - No parity
    	  - Hardware flow control disabled (RTS and CTS signals)
    	  - Receive and transmit enabled
    */
    USART_InitStructure.USART_BaudRate = BAUD_RATE ;
    USART_InitStructure.USART_WordLength = USART_WordLength_8b;
    USART_InitStructure.USART_StopBits = USART_StopBits_1;
    USART_InitStructure.USART_Parity = USART_Parity_No;
    USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
    USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;

    /* USART configuration */
    USART_Init(EXT_USART, &USART_InitStructure);

    /* Enable USART */
    USART_Cmd(EXT_USART, ENABLE);

}

uint16_t Checksum_u16(uint8_t *pdata, uint32_t len)
{
    uint16_t sum = 0;
    uint32_t i;
    for(i = 0; i < len; i++)
        sum += pdata[i];
    sum = ~sum;
    return sum;
}