你能用C语言写stm32使用SPI接口控制AD9851的程序吗

当然可以，以下是一个基本的示例程序：

#include "stm32f10x.h"

#define SPI_PORT                SPI1
#define SPI_SCK_PIN             GPIO_Pin_5
#define SPI_SCK_GPIO_PORT       GPIOA
#define SPI_MISO_PIN            GPIO_Pin_6
#define SPI_MISO_GPIO_PORT      GPIOA
#define SPI_MOSI_PIN            GPIO_Pin_7
#define SPI_MOSI_GPIO_PORT      GPIOA
#define AD9851_CS_PIN           GPIO_Pin_4
#define AD9851_CS_GPIO_PORT     GPIOA

void SPI_Configuration(void);
uint8_t SPI_SendByte(uint8_t byte);
void AD9851_Init(void);
void AD9851_SetFrequency(uint32_t frequency);

int main (void)
{
    SystemInit();

    SPI_Configuration();
    AD9851_Init();
    AD9851_SetFrequency(1000000);  // Set frequency to 1MHz

    while(1)
    {
        // Do something
    }
}

void SPI_Configuration(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;
    SPI_InitTypeDef SPI_InitStructure;

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_SPI1 | RCC_APB2Periph_GPIOA, ENABLE);

    /* Configure SPI pins */
    GPIO_InitStructure.GPIO_Pin = SPI_SCK_PIN | SPI_MOSI_PIN;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_Init(SPI_SCK_GPIO_PORT, &GPIO_InitStructure);

    GPIO_InitStructure.GPIO_Pin = SPI_MISO_PIN;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
    GPIO_Init(SPI_MISO_GPIO_PORT, &GPIO_InitStructure);

    /* Configure AD9851 CS pin */
    GPIO_InitStructure.GPIO_Pin = AD9851_CS_PIN;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
    GPIO_Init(AD9851_CS_GPIO_PORT, &GPIO_InitStructure);

    /* Configure SPI */
    SPI_InitStructure.SPI_Direction = SPI_Direction_1Line_Tx;
    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_4;
    SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB;
    SPI_Init(SPI_PORT, &SPI_InitStructure);

    SPI_Cmd(SPI_PORT, ENABLE);
}

uint8_t SPI_SendByte(uint8_t byte)
{
    /* Wait for the SPI transmit buffer to be empty */
    while (SPI_I2S_GetFlagStatus(SPI_PORT, SPI_I2S_FLAG_TXE) == RESET);

    /* Send the byte through the SPI peripheral */
    SPI_I2S_SendData(SPI_PORT, byte);

    /* Wait for the SPI receive buffer to be full */
    while (SPI_I2S_GetFlagStatus(SPI_PORT, SPI_I2S_FLAG_RXNE) == RESET);

    /* Return the received byte */
    return SPI_I2S_ReceiveData(SPI_PORT);
}

void AD9851_Init(void)
{
    /* Set the AD9851 to sleep mode */
    GPIO_ResetBits(AD9851_CS_GPIO_PORT, AD9851_CS_PIN);
    SPI_SendByte(0x00);
    SPI_SendByte(0x04);
    SPI_SendByte(0x00);
    SPI_SendByte(0x00);
    GPIO_SetBits(AD9851_CS_GPIO_PORT, AD9851_CS_PIN);
}

void AD9851_SetFrequency(uint32_t frequency)
{
    uint32_t freq_word = frequency * 4294967296.0 / 125000000.0;

    /* Set the AD9851 to frequency mode */
    GPIO_ResetBits(AD9851_CS_GPIO_PORT, AD9851_CS_PIN);
    SPI_SendByte(0x00);
    SPI_SendByte(0x02);
    SPI_SendByte((freq_word >> 24) & 0xFF);
    SPI_SendByte((freq_word >> 16) & 0xFF);
    SPI_SendByte((freq_word >> 8) & 0xFF);
    SPI_SendByte(freq_word & 0xFF);
    GPIO_SetBits(AD9851_CS_GPIO_PORT, AD9851_CS_PIN);
}

这个程序使用的是 STM32F1 系列的芯片，并且使用 SPI1 接口与 AD9851 芯片进行通信。SPI_SendByte 函数用于发送一个字节的数据，AD9851_Init 函数用于初始化 AD9851 芯片，AD9851_SetFrequency 函数用于设置 AD9851 的频率。注意，这个程序中的频率计算公式是针对 125MHz 的时钟频率的，如果使用的时钟频率不同，则需要相应地调整此公式。