STM32 AND ADS1299 SPI communication

  Recently, I want to  control the ADS1299 with STM32, but the spi communication is not correct. I followed the  diagram"Figure 56. Initial Flow at Power-Up" in the ADS1299 datasheet, but I don't know what's the problem with my code?

#include "stm32f10x.h"
#include "stm32f10x_usart.h"
#include "misc.h"
#include "stdarg.h"
#include "spi_ads1299.h"
#include "main.h"
#include "exti.h"

extern void SPI_ADS1299_Init(void);

/* Private function prototypes -----------------------------------------------*/
void RCC_Configuration(void);
void GPIO_Configuration(void);

void USART_Config(USART_TypeDef* USARTx);
void EXTI_PA0_Config(void); 

u8 SPI_ReadByte(void);
u8 SPI_SendByte(u8 byte);

char *itoa(int value, char *string, int radix);
void USART_OUT(USART_TypeDef* USARTx, uint8_t *Data,...);

void delay(uint32_t i);

/* global variable declaration */
uint16_t adc_temp;
uint8_t	spi_buffer[27];
uint8_t i;

uint8_t signal = 0;   //EXTI0中断标志

int main(void)
{
	RCC_Configuration();					   		//设置系统时钟  
   
	GPIO_Configuration();					    //IO口设置		 
  USART_Config(USART1);											  //串口1初始化
	EXTI_PA0_Config();                  //exti 中断设置
	SPI_ADS1299_Init();						    //SPI1 初始化
	
	
	//Set RESET = 1, Wait for 1s for Power-On Reset
	CS_HIGH;
	RESET_HIGH;

	delay(30);          

	
	USART_OUT(USART1,"* STEP 1 :\r\n");
	
	//Issue Reset Pulse
	RESET_LOW;
	delay(0xf);
	RESET_HIGH;
	delay(0x30);
	
	//Send SDATAC Command:  stop read data continuously mode
	spi_buffer[0] = 0x11;
	CS_LOW;
	SPI_SendByte(spi_buffer[0]);
	delay(0x02);
	CS_HIGH;
	
// 	//STOP
// 	spi_buffer[0] = 0x0A;
// 	CS_LOW;
// 	SPI_SendByte(spi_buffer[0]);
// 	delay(0x02);
// 	CS_HIGH;
// 	

	
	//If Using Internal Reference, Send Command-WREG CONFIG3 E0h 
	spi_buffer[0] = 0x43;  //write 1 register starting at address 03H(CONFIG3)
	spi_buffer[1] = 0x00;
	spi_buffer[2] = 0xE0;
	CS_LOW;
	for(i=0;i<3;i++)
	{
		SPI_SendByte(spi_buffer[i]);
		delay(0x02);
	}
	CS_HIGH;
		
	//Set Device for DR = fMOD/4096, WREG CONFIG1 96H
	spi_buffer[0] = 0x41;  //write 1 register starting at address 01H(CONFIG1)
	spi_buffer[1] = 0x00;
	spi_buffer[2] = 0x96;
	CS_LOW;
	for(i=0;i<3;i++)
		SPI_SendByte(spi_buffer[i]);
	delay(0x02);
	CS_HIGH;
		//Set Device for DR = fMOD/4096, WREG CONFIG2 C0H
	spi_buffer[0] = 0x42;  //write 1 register starting at address 02H(CONFIG2)
	spi_buffer[1] = 0x00;
	spi_buffer[2] = 0xC0;
	CS_LOW;
	for(i=0;i<3;i++)
		SPI_SendByte(spi_buffer[i]);
	delay(0x02);
	CS_HIGH;
	
	//Activate Conversion: Set START = 1;
	
// 	//config test signal
// 	spi_buffer[0] = 0x22;   //read 1 register starting at address 02H(CONFIG2)
// 	spi_buffer[1] = 0x00;
// // 	spi_buffer[2] = 0xC0;
// 	CS_LOW;	// CS	low
// 	for (i=0;i<2;i++)
// 		ReadWriteByte(spi_buffer[i]);
// 	spi_buffer[0]=ReadWriteByte(0x00);
// 	Delay_ms(1);
// 	CS_HIGH;	// CS high	
// 	
// 	spi_buffer[2] = 0x14 | spi_buffer[0];
// 	spi_buffer[1] = 0x00;
// 	spi_buffer[0] = 0x42;
// 	CS_LOW;	// CS	low
// 	for (i=0;i<3;i++)
// 		ReadWriteByte(spi_buffer[i]);
// 	Delay_ms(5);
// 	CS_HIGH;	// CS high	
// 	
// 	// CONFIG CH1 for test signal
// 	spi_buffer[0]	=	0x25;  
// 	spi_buffer[1]	=	0x00;
// 	spi_buffer[2]	=	0x00;
// 	CS_LOW;	// CS	low
//   for (i=0;i<2;i++)
// 		ReadWriteByte(spi_buffer[i]);
// 	spi_buffer[0]=ReadWriteByte(0x00);
// 	Delay_ms(5);
// 	CS_HIGH;	// CS high
// 	
// 	spi_buffer[2] = 0x5 | spi_buffer[0];
// 	spi_buffer[1] = 0x00;
// 	spi_buffer[0] = 0x45;
// 	CS_LOW;	// CS	low
//   for (i=0;i<3;i++)
// 		ReadWriteByte(spi_buffer[i]);
// 	Delay_ms(5);
// 	CS_HIGH;	// CS high

		// START /
	spi_buffer[0]	=	0x08;
	CS_LOW;	// CS	low
  SPI_SendByte(spi_buffer[0]);
	delay(0x0f);
	CS_HIGH;	// CS high
	
	// RDATAC /Enable Read Data Continuous mode
	spi_buffer[0]	=	0x10;
	CS_LOW;	// CS	low
  SPI_SendByte(spi_buffer[0]);
	delay(0x0f);
	CS_HIGH;	// CS high

	NVIC_EnableIRQ(EXTI0_IRQn);
	
   while(1)
	 {
		 if(signal == 1)
		 {
				for(i=0;i<27;i++)
				{
					USART_OUT(USART1,"spi_buffer[%d] = %d",i,spi_buffer[i]);  
					USART_OUT(USART1," ");  
				}
				USART_OUT(USART1,"\r\n");  
			}
		}
}
/*
*简单软件延时函数ms
*/
void delay(uint32_t i)
{
	 uint32_t j;
	for (j=0; j!=i*1000; j++)
	;
}

/****************************************************************************
* 名    称：void USART_OUT(USART_TypeDef* USARTx, uint8_t *Data,...)
* 功    能：格式化串口输出函数
* 入口参数：USARTx:  指定串口
			Data：   发送数组
			...:     不定参数
* 出口参数：无
* 说    明：格式化串口输出函数
        	"\r"	回车符	   USART_OUT(USART1, "abcdefg\r")   
			"\n"	换行符	   USART_OUT(USART1, "abcdefg\r\n")
			"%s"	字符串	   USART_OUT(USART1, "字符串是：%s","abcdefg")
			"%d"	十进制	   USART_OUT(USART1, "a=%d",10)
* 调用方法：无 
****************************************************************************/
void USART_OUT(USART_TypeDef* USARTx, uint8_t *Data,...){ 
	const char *s;
    int d;
    char buf[16];
    va_list ap;
    va_start(ap, Data);

	while(*Data!=0){				                          //判断是否到达字符串结束符
		if(*Data==0x5c){									  //'\'
			switch (*++Data){
				case 'r':							          //回车符
					USART_SendData(USARTx, 0x0d);	   

					Data++;
					break;
				case 'n':							          //换行符
					USART_SendData(USARTx, 0x0a);	
					Data++;
					break;
				
				default:
					Data++;
				    break;
			}
			
			 
		}
		else if(*Data=='%'){									  //
			switch (*++Data){				
				case 's':										  //字符串
                	s = va_arg(ap, const char *);
                	for ( ; *s; s++) {
                    	USART_SendData(USARTx,*s);
						while(USART_GetFlagStatus(USARTx, USART_FLAG_TC)==RESET);
                	}
					Data++;
                	break;
            	case 'd':										  //十进制
                	d = va_arg(ap, int);
                	itoa(d, buf, 10);
                	for (s = buf; *s; s++) {
                    	USART_SendData(USARTx,*s);
						while(USART_GetFlagStatus(USARTx, USART_FLAG_TC)==RESET);
                	}
					Data++;
                	break;
				default:
					Data++;
				    break;
			}		 
		}
		else USART_SendData(USARTx, *Data++);
		while(USART_GetFlagStatus(USARTx, USART_FLAG_TC)==RESET);
	}
}

/******************************************************
		整形数据转字符串函数
        char *itoa(int value, char *string, int radix)
		radix=10 标示是10进制	非十进制，转换结果为0;  

	    例：d=-379;
		执行	itoa(d, buf, 10); 后
		
		buf="-379"							   			  
**********************************************************/
char *itoa(int value, char *string, int radix)
{
    int     i, d;
    int     flag = 0;
    char    *ptr = string;

    /* This implementation only works for decimal numbers. */
    if (radix != 10)
    {
        *ptr = 0;
        return string;
    }

    if (!value)
    {
        *ptr++ = 0x30;
        *ptr = 0;
        return string;
    }

    /* if this is a negative value insert the minus sign. */
    if (value < 0)
    {
        *ptr++ = '-';

        /* Make the value positive. */
        value *= -1;
    }

    for (i = 10000; i > 0; i /= 10)
    {
        d = value / i;

        if (d || flag)
        {
            *ptr++ = (char)(d + 0x30);
            value -= (d * i);
            flag = 1;
        }
    }

    /* Null terminate the string. */
    *ptr = 0;

    return string;

} /* NCL_Itoa */

/****************************************************************************
* 名    称：USART_Config(USART_TypeDef* USARTx)
* 功    能：配置串口
* 入口参数：
* 出口参数：无
* 说    明：
* 调用方法：例如: USART_Config(USART1)
****************************************************************************/
void USART_Config(USART_TypeDef* USARTx){
	USART_InitTypeDef USART_InitStructure;
	
  USART_InitStructure.USART_BaudRate = 115200;						//速率115200bps
  USART_InitStructure.USART_WordLength = USART_WordLength_8b;		//数据位8位
  USART_InitStructure.USART_StopBits = USART_StopBits_1;			//停止位1位
  USART_InitStructure.USART_Parity = USART_Parity_No;				//无校验位
  USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;   //无硬件流控
  USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;					//收发模式

  /* Configure USART1 */
  USART_Init(USARTx, &USART_InitStructure);							//配置串口参数函数
 
  
//   /* Enable USART1 Receive and Transmit interrupts */
//   USART_ITConfig(USART1, USART_IT_RXNE, ENABLE);                    //使能接收中断
//   USART_ITConfig(USART1, USART_IT_TXE, ENABLE);						//使能发送缓冲空中断   

  /* Enable the USART1 */
  USART_Cmd(USART1, ENABLE);	
}


/****************************************************************************
* 名    称：void RCC_Configuration(void)
* 功    能：系统时钟配置为72MHZ， 外设时钟配置
* 入口参数：无
* 出口参数：无
* 说    明：
* 调用方法：无 
****************************************************************************/ 
void RCC_Configuration(void){

  SystemInit();	  
  
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO, ENABLE);
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1 | RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOB | RCC_APB2Periph_GPIOC 
  						| RCC_APB2Periph_GPIOD| RCC_APB2Periph_GPIOE , ENABLE);
}

/****************************************************************************
* 名    称：void GPIO_Configuration(void)
* 功    能：通用IO口配置
* 入口参数：无
* 出口参数：无
* 说    明：
* 调用方法：
****************************************************************************/  
void GPIO_Configuration(void)
{
  GPIO_InitTypeDef GPIO_InitStructure;
	
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;	         		 //USART1 TX
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;    		 //复用推挽输出
  GPIO_Init(GPIOA, &GPIO_InitStructure);		    		 //A端口 

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;	         	 //USART1 RX
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;   	 //复用开漏输入
  GPIO_Init(GPIOA, &GPIO_InitStructure);		         	 //A端口 
	
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1;				     //PA1 RESET
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;			 //通用推挽输出模式
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;			 //输出模式最大速度50MHz
  GPIO_Init(GPIOA, &GPIO_InitStructure); 
	
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5;				     //状态LED1
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;			 //通用推挽输出模式
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;			 //输出模式最大速度50MHz
  GPIO_Init(GPIOB, &GPIO_InitStructure); 	
			  
}

/******************* **********************************END OF FILE************/

Does anyone has experience to use STM32 to control the ADS1299?