SPI硬件NSS无输出，空闲状态已经设置为高

只看该作者 · 2023-12-13 23:21

本帖最后由地瓜ing 于 2023-12-13 23:25 编辑

在调试SPI的过程中遇到使用硬件NSS时，对应的IO没有输出的问题，以下是相应代码
PA15作为SPI1的硬件NSS引脚一直输出低电平，AFIO中SPI1的NSS空闲状态已经设置为高电平了，还是一直输出低电平
以下是初始化程序
void Spi1GpioConfig()
{
GPIO_InitType GPIO_InitStructure;
/* Initialize GPIO_InitStructure */
GPIO_Structure_Initialize(&GPIO_InitStructure);
RCC_AHB_Peripheral_Clock_Enable(RCC_AHB_PERIPH_GPIOA|RCC_AHB_PERIPH_GPIOB);
RCC_APB2_Peripheral_Clock_Enable(RCC_APB2_PERIPH_AFIO);

GPIO_InitStructure.Pin       = GPIO_PIN_3 | GPIO_PIN_4 ;//PB3->SCK,PB4->MISO
GPIO_InitStructure.GPIO_Mode  = GPIO_MODE_AF_PP;
GPIO_InitStructure.GPIO_Slew_Rate = GPIO_SLEW_RATE_FAST;
GPIO_InitStructure.GPIO_Alternate = GPIO_AF2_SPI1;
GPIO_Peripheral_Initialize(GPIOB, &GPIO_InitStructure);

GPIO_InitStructure.Pin       = GPIO_PIN_5 ;                                              //PB5->MOSI
GPIO_InitStructure.GPIO_Alternate = GPIO_AF1_SPI1;
GPIO_Peripheral_Initialize(GPIOB, &GPIO_InitStructure);

GPIO_InitStructure.Pin                               = GPIO_PIN_15 ;                                              //PA15->NSS
GPIO_InitStructure.GPIO_Alternate = GPIO_AF1_SPI1;
GPIO_Peripheral_Initialize(GPIOA, &GPIO_InitStructure);
AFIO_SPI_NSS_Mode_Set(AFIO_SPI1_NSS, AFIO_SPI_NSS_High_LEVEL);//NSS空闲时的电平
}

void Spi1_Init ( void )
{
      SPI_InitType SPI_InitStructure;
      SPI_I2S_Reset(SPI1);
      Spi1GpioConfig();

      RCC_APB2_Peripheral_Clock_Enable(RCC_APB2_PERIPH_SPI1);
/* SPI_MASTER configuration ------------------------------------------------------*/
  SPI_Initializes_Structure(&SPI_InitStructure);
  SPI_InitStructure.DataDirection = SPI_DIR_DOUBLELINE_FULLDUPLEX;
  SPI_InitStructure.SpiMode    = SPI_MODE_MASTER;
  SPI_InitStructure.DataLen    = SPI_DATA_SIZE_8BITS;
  SPI_InitStructure.CLKPOL       = SPI_CLKPOL_HIGH;
  SPI_InitStructure.CLKPHA       = SPI_CLKPHA_SECOND_EDGE;
  SPI_InitStructure.NSS          = SPI_NSS_HARD;
  /* It is recommended that the SPI master mode of the C version chips should not exceed 18MHz */
  SPI_InitStructure.BaudRatePres  = SPI_BR_PRESCALER_32;
  SPI_InitStructure.FirstBit    = SPI_FB_MSB;
  SPI_InitStructure.CRCPoly    = 7;
  SPI_Initializes(SPI1, &SPI_InitStructure);
  SPI_SS_Output_Enable(SPI1);

  SPI_ON(SPI1);
}

以下是主循环中的测试部分

      while(1)
      {
            if(Task_TimeFlag_ms(1,100))
            {
                     //100ms运行一次
                     Run();
//                SPI_Set_Nss_Level(SPI1, SPI_NSS_LOW);
                     SPI_I2S_Data_Transmit(SPI1, 0x5A);
                     Delay_Us(100);
                     SPI_I2S_Data_Transmit(SPI1, 0xA5);
//                SPI_Set_Nss_Level(SPI1, SPI_NSS_HIGH);
                     LED_TOGGLE;
            }
      }

只看该作者 · 2023-12-14 21:17

有没有哪位大神帮忙分析一下问题呀