STM32 SPI通讯DA转换问题

只看该作者 · 2012-3-13 23:37

大家好！

   我用STM32和AD5660通讯做DA转换输出锯齿波，出现附图的波形问题，麻烦帮忙看看，谢谢！AD5660是24位数据输出。
/* Includes ------------------------------------------------------------------*/
#include "stm32f10x_lib.h"
/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
//----------------------------------------------
#define SPI_FLAG_RXNE          SPI_I2S_FLAG_RXNE
#define SPI_FLAG_TXE          SPI_I2S_FLAG_TXE
#define SPI_FLAG_OVR          SPI_I2S_FLAG_OVR
#define SPI_FLAG_BSY          SPI_I2S_FLAG_BSY
//----------------------------------------------
#define SPI_GetFlagStatus    SPI_I2S_GetFlagStatus
#define SPI_SendData          SPI_I2S_SendData
#define SPI_ReceiveData       SPI_I2S_ReceiveData

/* Private variables ---------------------------------------------------------*/
GPIO_InitTypeDef GPIO_InitStructure;
SPI_InitTypeDef  SPI_InitStructure;
ErrorStatus HSEStartUpStatus;
/* Private function prototypes -----------------------------------------------*/
void RCC_Configuration(void);
void NVIC_Configuration(void);
void Delay(vu32 nCount);
void SPI_SendByte(u8 byte);
void SPI2_Init(void);
u8 SPI_Send_Byte(u8 dat);

/* Private functions ---------------------------------------------------------*/
/*******************************************************************************
* Function Name  : main
* Description : Main program.
* Input       : None
* Output       : None
* Return       : None
*******************************************************************************/
int main(void)
{
#ifdef DEBUG
  debug();
#endif
  vu16 Test1=0;
  vu16 Test2=0;
  RCC_Configuration(); //系统时钟配置函数
  NVIC_Configuration();  //NVIC配置函数
  //使能APB2总线外设时钟
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOB | RCC_APB2Periph_AFIO, ENABLE);
  GPIO_PinRemapConfig(GPIO_Remap_SWJ_Disable, ENABLE);  //关闭调试端口重新映射
  SPI2_Init();

while (1)
  {

//GPIO_Write(GPIOB, ~Test1); //写一个字数据到PB口
GPIO_SetBits(GPIOB, GPIO_Pin_12);
Delay(0x000F);
GPIO_ResetBits(GPIOB, GPIO_Pin_12);
SPI_Send_Byte(0x00);
//SPI_Send_Byte(0x00);
SPI_Send_Byte(Test1>>8); //发送数据到SPI缓存
SPI_Send_Byte(Test1&0x00ff);
Delay(0x000F);
if(Test1==0x9fff)
{
Test1=0;
}
Test1++;
//GPIO_SetBits(GPIOB, GPIO_Pin_12); //片选
  }
}

void SPI2_Init(void)
{
  SPI_InitTypeDef  SPI_InitStructure;
  GPIO_InitTypeDef GPIO_InitStructure;


  RCC_APB1PeriphClockCmd(RCC_APB1Periph_SPI2, ENABLE);

  /* Configure SPI2 pins: NSS, SCK, MISO and MOSI */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_13 | GPIO_Pin_14 | GPIO_Pin_15;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
  GPIO_Init(GPIOB, &GPIO_InitStructure);
/*Configure PA.4(NSS)--------------------------------------------*/
  GPIO_InitStructure.GPIO_Pin =GPIO_Pin_12;
  GPIO_InitStructure.GPIO_Mode=GPIO_Mode_Out_PP;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_Init(GPIOB, &GPIO_InitStructure);

  //GPIO_InitStructure.GPIO_Pin = GPIO_Pin_12 | GPIO_Pin_13 | GPIO_Pin_14;
  //GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  //GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
  //GPIO_Init(GPIOA, &GPIO_InitStructure);

  /* SPI1 configuration */
  SPI_InitStructure.SPI_Direction = SPI_Direction_2Lines_FullDuplex;
  SPI_InitStructure.SPI_Mode = SPI_Mode_Master;  //主机模式
  SPI_InitStructure.SPI_DataSize = SPI_DataSize_8b; //8位数据
  SPI_InitStructure.SPI_CPOL = SPI_CPOL_Low;//SPI_CPOL_High=模式3，时钟空闲为高 //SPI_CPOL_Low=模式0，时钟空闲为低
  SPI_InitStructure.SPI_CPHA = SPI_CPHA_1Edge;//SPI_CPHA_2Edge;//SPI_CPHA_1Edge, SPI_CPHA_2Edge;
  SPI_InitStructure.SPI_NSS = SPI_NSS_Soft;//SPI_NSS_Soft;//SPI_NSS_Hard
  SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_4;//SPI_BaudRatePrescaler_2=18M;//SPI_BaudRatePrescaler_4=9MHz
  SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB;//数据从高位开始发送
  SPI_InitStructure.SPI_CRCPolynomial = 7;

  SPI_Init(SPI2, &SPI_InitStructure);
/*Enable SPI1.NSS as a GPIO*/
  SPI_SSOutputCmd(SPI2, ENABLE);
  /* Enable SPI2  */
  SPI_Cmd(SPI2, ENABLE);
}

/*******************************************************************************
* Function Name  : SPI_FLASH_SendByte
* Description : Sends a byte through the SPI interface and return the byte
*                received from the SPI bus.
* Input       : byte : byte to send.
* Output       : None
* Return       : The value of the received byte.
*******************************************************************************/
u8 SPI_Send_Byte(u8 dat)
{
  /* Loop while DR register in not emplty */
  while(SPI_GetFlagStatus(SPI2, SPI_FLAG_TXE) == RESET);
  /* Send byte through the SPI2 peripheral */
  SPI_SendData(SPI2, dat);
  /* Wait to receive a byte */
  while(SPI_GetFlagStatus(SPI2, SPI_FLAG_RXNE) == RESET);
  /* Return the byte read from the SPI bus */
  return SPI_ReceiveData(SPI2);
}

/*******************************************************************************
* Function Name  : RCC_Configuration
* Description : Configures the different system clocks.
* Input       : None
* Output       : None
* Return       : None
*******************************************************************************/
void RCC_Configuration(void)
{
  /* RCC system reset(for debug purpose) */
  RCC_DeInit();
  /* Enable HSE */
  RCC_HSEConfig(RCC_HSE_ON);
  /* Wait till HSE is ready */
  HSEStartUpStatus = RCC_WaitForHSEStartUp();
  if(HSEStartUpStatus == SUCCESS)
  {
/* Enable Prefetch Buffer */
FLASH_PrefetchBufferCmd(FLASH_PrefetchBuffer_Enable);
/* Flash 2 wait state */
FLASH_SetLatency(FLASH_Latency_2);

/* HCLK = SYSCLK */
RCC_HCLKConfig(RCC_SYSCLK_Div1);

/* PCLK2 = HCLK */
RCC_PCLK2Config(RCC_HCLK_Div1);
/* PCLK1 = HCLK/2 */
RCC_PCLK1Config(RCC_HCLK_Div2);
/* PLLCLK = 8MHz * 9 = 72 MHz */
RCC_PLLConfig(RCC_PLLSource_HSE_Div1, RCC_PLLMul_9);
/* Enable PLL */
RCC_PLLCmd(ENABLE);
/* Wait till PLL is ready */
while(RCC_GetFlagStatus(RCC_FLAG_PLLRDY) == RESET)
{
}
/* Select PLL as system clock source */
RCC_SYSCLKConfig(RCC_SYSCLKSource_PLLCLK);
/* Wait till PLL is used as system clock source */
while(RCC_GetSYSCLKSource() != 0x08)
{
}
  }
}
/*******************************************************************************
* Function Name  : NVIC_Configuration
* Description : Configures Vector Table base location.
* Input       : None
* Output       : None
* Return       : None
*******************************************************************************/
void NVIC_Configuration(void)
{
#ifdef  VECT_TAB_RAM
  /* Set the Vector Table base location at 0x20000000 */
  NVIC_SetVectorTable(NVIC_VectTab_RAM, 0x0);
#else  /* VECT_TAB_FLASH  */
  /* Set the Vector Table base location at 0x08000000 */
  NVIC_SetVectorTable(NVIC_VectTab_FLASH, 0x0);
#endif
}
/*******************************************************************************
* Function Name  : Delay
* Description : Inserts a delay time.
* Input       : nCount: specifies the delay time length.
* Output       : None
* Return       : None
*******************************************************************************/
void Delay(vu32 nCount)
{
  for(; nCount != 0; nCount--);
}
#ifdef  DEBUG
/*******************************************************************************
* Function Name  : assert_failed
* Description : Reports the name of the source file and the source line number
*                where the assert_param error has occurred.
* Input       : - file: pointer to the source file name
*                - line: assert_param error line source number
* Output       : None
* Return       : None
*******************************************************************************/
void assert_failed(u8* file, u32 line)
{
  /* User can add his own implementation to report the file name and line number,
   ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
  /* Infinite loop */
  while (1)
  {
  }
}
#endif
/******************* (C) COPYRIGHT 2008 STMicroelectronics *****END OF FILE****/