求stm32合vs1053通讯问题

只看该作者 · 2011-6-3 17:52

小弟刚接触STM32，现用stm32的spi1与vs1053通讯
初始化如下：
SPI_InitTypeDef SPI_InitStructure;
GPIO_InitTypeDef  GPIO_InitStructure;

//和spi相关的I/O口
/* Configure PA4 pin: CS pin  MP3芯片选择引脚*/
   GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4;
   GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
   GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
   GPIO_Init(GPIOA, &GPIO_InitStructure);

   /* Configure PA5 6 7 pin: SCK  MISO  MOSI  pin  */
   GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5 | GPIO_Pin_6 | GPIO_Pin_7;
   GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
   GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
   GPIO_Init(GPIOA, &GPIO_InitStructure);
   RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA
                        | RCC_APB2Periph_AFIO
                        | RCC_APB2Periph_SPI1
                        ,ENABLE);


   /*  SPI 初始化  */
   SPI_InitStructure.SPI_Direction = SPI_Direction_2Lines_FullDuplex; //双工模式
   SPI_InitStructure.SPI_Mode = SPI_Mode_Master; //SPI主模式
   SPI_InitStructure.SPI_DataSize = SPI_DataSize_8b; //8bit数据
   SPI_InitStructure.SPI_CPOL = SPI_CPOL_Low; //CLK空闲时为低电平
   SPI_InitStructure.SPI_CPHA = SPI_CPHA_1Edge; //上升沿采样
   SPI_InitStructure.SPI_NSS = SPI_NSS_Soft; //片选用软件控制
   SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_64; //SPI频率
   SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB; //高位在前
   SPI_InitStructure.SPI_CRCPolynomial = 7; //crc7，stm32spi带硬件ecc
   SPI_Init(SPI1, &SPI_InitStructure);


   SPI_Cmd(SPI1, ENABLE);

收发一个字节的函数如下：
   i = data;
   while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_TXE) == RESET)
   {
      if(++j>100)
      {
         return(55);
      }
   }

   SPI_I2S_SendData(SPI1, i);

   j = 0;
   while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_RXNE) == RESET)
   {
      if(++j>100)
      {
         return(55);
      }
   }

   return SPI_I2S_ReceiveData(SPI1);

对spi1写一个字节接收到的竟然也是这个字节，比如对spi写55，收到的也是55，这算不算正确啊？还有，这要是正确的话，我怎么对vs1053模块写命令却没有反应啊？？？？？？？？
望牛人指点一二，小弟万分感激！