error in MOSI

Hi everyone
i am a beginner in SPI. i am using STM32F051 discovery board. DAC081S151 is used as the slave in this commmunication.I view the output on CRO. The MOSI out is in correct. Please help me to get the DAC output.Tne code i used is given below.

 #include <stdio.h>
#include "stm32f0xx.h"
#include "stm32f0xx_gpio.h"
#include "stm32f0xx_it.h"
#include "stm32f0xx_rcc.h"

#include "stm32f0xx_usart.h"
#include "stm32f0xx_conf.h"
#include "stm32f0xx_adc.h"
#include "stm32f0xx_i2c.h"

#include "math.h"
#include "string.h"
#include "main.h"


#include "main.h"
void delay_ns(unsigned int d){  /* Not exact value, for 168 MHz @ Level3 Opt */
        unsigned int i;
        i=d/25;while(i)i--;
}

void delay_us(unsigned int d){  /* for 168 MHz @ Level3 Opt */
        unsigned int i,j;
        i=d;while(i){i--;j=55;while(j)j--;}
}
void delay_ms(unsigned int d){  /* for 168 MHz @ Level3 Opt */
        unsigned int i;
        i=d;while(i){i--;delay_us(250);}
}

void spiInit(void);


void spiInit()
{
  SPI_InitTypeDef SPI_InitStructure;
     GPIO_InitTypeDef GPIO_InitStructure;

     RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA | RCC_AHBPeriph_GPIOB ,ENABLE);
  RCC_APB2PeriphClockCmd (RCC_APB2Periph_SPI1, ENABLE);


  SPI_InitStructure.SPI_Direction = SPI_Direction_2Lines_FullDuplex;

  SPI_InitStructure.SPI_Mode = SPI_Mode_Master;
  SPI_InitStructure.SPI_DataSize = SPI_DataSize_8b;
  SPI_InitStructure.SPI_CPOL = SPI_CPOL_Low;
  SPI_InitStructure.SPI_CPHA = SPI_CPHA_1Edge;
  SPI_InitStructure.SPI_NSS = SPI_NSS_Soft;
  SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_256;//32
  SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB;
  SPI_InitStructure.SPI_CRCPolynomial = 7;
        SPI_Init(SPI1, &SPI_InitStructure);

     /////////////////////////////////////////////////////////////////////////////
     // SPI1 Master initialization, SCK -> PA5, MOSI -> PA7
     GPIO_StructInit (&GPIO_InitStructure);
     GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5 | GPIO_Pin_7;
     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_UP  ; //PuPd_UP
     GPIO_Init(GPIOA, &GPIO_InitStructure);
     GPIO_PinAFConfig(GPIOA, GPIO_PinSource5, GPIO_AF_0);
     GPIO_PinAFConfig(GPIOA, GPIO_PinSource7, GPIO_AF_0);

     // MISO -> PA6
     GPIO_StructInit (&GPIO_InitStructure);
     GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6;
     GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN;
     GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
     GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
     GPIO_Init(GPIOA, &GPIO_InitStructure);
     GPIO_PinAFConfig(GPIOA, GPIO_PinSource6, GPIO_AF_0);

     // CS or SS chip select -> PA4
     GPIO_StructInit (&GPIO_InitStructure);
     GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4;
     GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT;
     GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
     GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
     GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP ;
     GPIO_Init(GPIOA, &GPIO_InitStructure);

     // SPI1
  SPI_Init(SPI1, &SPI_InitStructure);
  SPI_RxFIFOThresholdConfig(SPI1, SPI_RxFIFOThreshold_QF);
        SPI_SSOutputCmd(SPI1,ENABLE);
  SPI_Cmd(SPI1, ENABLE);

}


void ChipSelectLow()
{
     GPIO_WriteBit(GPIOA, GPIO_Pin_4, Bit_RESET);
}


void ChipSelectHigh ()
{
     GPIO_WriteBit(GPIOA, GPIO_Pin_4, Bit_SET);
}


uint8_t SPI1_send(uint8_t data){


     SPI1->DR = data; // write data to be transmitted to the SPI data register
     while( !(SPI1->SR & SPI_I2S_FLAG_TXE) ); // wait until transmit complete
     while( !(SPI1->SR & SPI_I2S_FLAG_RXNE) ); // wait until receive complete
     while( SPI1->SR & SPI_I2S_FLAG_BSY ); // wait until SPI is not busy anymore
     return SPI1->DR; // return received data from SPI data register
}




int main()
{

         while (1)
         {
     spiInit();


  ChipSelectHigh ();
  //*********************************
  ChipSelectLow ();
   SPI_SendData8(SPI1 , 0x055);
//  SPI_SendData8(SPI1 , 0x55);
     while( !(SPI1->SR & SPI_I2S_FLAG_TXE) ); // wait until transmit complete
     while( !(SPI1->SR & SPI_I2S_FLAG_RXNE) ); // wait until receive complete
     while( SPI1->SR & SPI_I2S_FLAG_BSY ); // wait until SPI is not busy anymore
  ChipSelectHigh ();


  }

}

.