FAQs
cancel
Turn on suggestions
Auto-suggest helps you quickly narrow down your search results by suggesting possible matches as you type.
Showing results for 
Search instead for 
Did you mean: 

SPI NSS Hardware control

Kim.Andy
Associate III

‎2013-04-30 01:51 AM

Posted on April 30, 2013 at 10:51

Hello,

I have a problem with SPI communication in case of NSS Hardware control.

NSS of SPI Signal is always low.

I know that it is low when SPI is enable, and high when SPI is disable.

But it is always low. why?

The following is my program related with SPI.

==============================================================

void bsp_init_rcc(void)

{ 

 /* SYSCLK, HCLK, PCLK2 and PCLK1 configuration -----------------------------*/  

 /* 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);

  /* PCLK2 = HCLK/2 */

//  RCC_PCLK2Config(RCC_HCLK_Div2);

  /* PCLK1 = HCLK/2 */

  RCC_PCLK1Config(RCC_HCLK_Div2);

#if defined( STM32F10X_CL )

  /* Configure PLLs *********************************************************/

  /* PLL2 configuration: PLL2CLK = (HSE / 5) * 8 = 40 MHz */

  RCC_PREDIV2Config(RCC_PREDIV2_Div5);

  RCC_PLL2Config(RCC_PLL2Mul_8);

  /* Enable PLL2 */

  RCC_PLL2Cmd(ENABLE);

  /* Wait till PLL2 is ready */

  while (RCC_GetFlagStatus(RCC_FLAG_PLL2RDY) == RESET)

  {}

 #if defined (HSE_8MHZ)

  /* PLL configuration: PLLCLK = (PLL2 / 5) * 9 = 72 MHz */

  RCC_PREDIV1Config(RCC_PREDIV1_Source_PLL2, RCC_PREDIV1_Div5);  

  RCC_PLLConfig(RCC_PLLSource_PREDIV1, RCC_PLLMul_9);

 #endif

#else

 #if defined (HSE_12MHZ)

  /* PLLCLK = 12MHz * 6 = 72 MHz */

  RCC_PLLConfig(RCC_PLLSource_HSE_Div1, RCC_PLLMul_6);

 #elif defined( HSE_16MHZ )

  /* PLLCLK = 16MHz /2 * 9 = 72 MHz */

  RCC_PLLConfig(RCC_PLLSource_HSE_Div2, RCC_PLLMul_9);

 #else  // 8MHZ  

  /* PLLCLK = 8MHz * 9 = 72 MHz */

  RCC_PLLConfig(RCC_PLLSource_HSE_Div1, RCC_PLLMul_9);

 #endif

#endif

  /* 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)

  {

  }

  }

  else

  { /* If HSE fails to start-up, the application will have wrong clock configuration.

     User can add here some code to deal with this error */   

  /* Go to infinite loop */

  while (1)

  {

  }

 }

 

 /* enable the PWR clock */

 RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWR, ENABLE);

 /* Enable GPIOA, GPIOB, GPIOC, GPIOD, GPIOE and AFIO clocks */

 RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOB |RCC_APB2Periph_GPIOC | RCC_APB2Periph_GPIOD | RCC_APB2Periph_GPIOE | RCC_APB2Periph_AFIO, ENABLE);

 /* USART1 Periph clock enable */

 RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE);

 /* TIM1 Periph clock enable */

 // RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1, ENABLE);

 /* TIM2 clock enable */

 RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE); 

 Set_USBClock();

   /* Enable peripheral clocks --------------------------------------------------*/

  /* SPI1 clock enable */

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_SPI1, ENABLE);

  /* SPI2 Periph clock enable */

  RCC_APB1PeriphClockCmd(RCC_APB1Periph_SPI2, ENABLE);

}

void bsp_init_gpio(void)

{

  GPIO_InitTypeDef GPIO_InitStructure;

  /* Configure the GPIO ports( leds ) */

  GPIO_InitStructure.GPIO_Pin =  LED_USER_PIN;

  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;

  GPIO_Init(LED_USER_PORT, &GPIO_InitStructure); 

  /* GPIOA Configuration:TIM2 Channel1, 2, 3 and 4 in Output */

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0 | GPIO_Pin_1 | GPIO_Pin_2 | GPIO_Pin_3;

  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;

  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

 

  GPIO_Init(GPIOA, &GPIO_InitStructure); 

  /* Configure SPI1 pins: SCK, MISO and MOSI ---------------------------------*/

  /* Confugure NSS, SCK and MOSI pins as Alternate Function Push Pull */

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4 | GPIO_Pin_5 | GPIO_Pin_7;

  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;

  GPIO_Init(GPIOA, &GPIO_InitStructure);

 

 /* Confugure MISO pin as Input Floating  */

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6;

  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;

  GPIO_Init(GPIOA, &GPIO_InitStructure);

}

void spi_test(void)

{

  /* SPI1 configuration ------------------------------------------------------*/

  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_Low;

  SPI_InitStructure.SPI_CPHA = SPI_CPHA_1Edge;

  SPI_InitStructure.SPI_NSS = SPI_NSS_Hard;

  SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_4;

  SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB;

  SPI_InitStructure.SPI_CRCPolynomial = 7;

  SPI_Init(SPI1, &SPI_InitStructure);

 

  /* Enable SPI1 CRC calculation */

  SPI_CalculateCRC(SPI1, ENABLE);

  SPI_SSOutputCmd(SPI1, ENABLE);

  /* Enable SPI1 */

  SPI_Cmd(SPI1, ENABLE);

  /* Transfer procedure */

  /* Wait for SPI1 Tx buffer empty */

  while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_TXE) == RESET);

  /* Send SPI2 data */

  SPI_I2S_SendData(SPI1, SPI1_Buffer_Tx[TxIdx++]);

}

==============================================================

Is there any error for NSS Control?
0 Kudos
1 REPLY 1
Top