请教下香主SPI1使用主模式了，那么PA4是否可以用于DA输出？

只看该作者 · 2014-8-21 10:35

今天试了一下，把PA4设置成DA输出后，再设置SPI1，发现SPI1不工作了。是怎么回事？

      DAC_InitTypeDef DAC_InitStructure;
GPIO_InitTypeDef GPIO_InitStructure;
/* GPIOA Periph clock enable */
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
/* DAC Periph clock enable */
RCC_APB1PeriphClockCmd(RCC_APB1Periph_DAC, ENABLE);
/* TIM6 Periph clock enable */
GPIO_InitStructure.GPIO_Pin =  GPIO_Pin_4;//GPIO_Pin_4;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN;
GPIO_Init(GPIOA, &GPIO_InitStructure);
/* DAC channel1 Configuration */
DAC_InitStructure.DAC_Trigger = DAC_Trigger_None;
DAC_InitStructure.DAC_WaveGeneration = DAC_WaveGeneration_None;
DAC_InitStructure.DAC_OutputBuffer = DAC_OutputBuffer_Enable;//DAC_OutputBuffer_Disable;
DAC_Init(DAC_Channel_1, &DAC_InitStructure);
DAC_Cmd(DAC_Channel_1, ENABLE);

      GPIO_InitStructure.GPIO_Pin = SPI_MASTER_PIN_SCK|SPI_MASTER_PIN_MISO|SPI_MASTER_PIN_MOSI;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_OD;
GPIO_Init(SPI_MASTER_GPIO, &GPIO_InitStructure);

   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_High;
  SPI_InitStructure.SPI_CPHA = SPI_CPHA_2Edge;
  SPI_InitStructure.SPI_NSS = SPI_NSS_Soft;
  SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_256;
  SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB;
  SPI_InitStructure.SPI_CRCPolynomial = 7;
  SPI_Init(SPI_MASTER, &SPI_InitStructure);
  SPI_Cmd(SPI_MASTER, ENABLE);