SPI MISO line stays high?

[HJain.3]

I am writing a driver for the STM32 to get the data from the front-end board, AD5940 using the SPI communication. I am using the AD5940 library available at the : https://github.com/analogdevicesinc/ad5940lib.

STM32WB55xx has been used. I have configured the SPI clock to the < AD5940 clock speed.

Added the SPI and CS pin configuration in cube mx.

whenever I am trying to read the chipid, I am always getting ffff. Also, When projecting the MISO line on the digital analyzer, observing the miso line stays high always. Please find the cubemx main.c file for reference:

[HJain.3]

/* Includes ------------------------------------------------------------------*/
#include "main.h"
 
/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */
#include "AD5940.h"
/* USER CODE END Includes */
 
/* Private typedef -----------------------------------------------------------*/
/* USER CODE BEGIN PTD */
 
/* USER CODE END PTD */
 
/* Private define ------------------------------------------------------------*/
/* USER CODE BEGIN PD */
/* USER CODE END PD */
 
/* Private macro -------------------------------------------------------------*/
/* USER CODE BEGIN PM */
 
/* USER CODE END PM */
 
/* Private variables ---------------------------------------------------------*/
SPI_HandleTypeDef hspi1;
 
/* USER CODE BEGIN PV */
 
/* USER CODE END PV */
 
/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
void PeriphCommonClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_SPI1_Init(void);
/* Private user code ---------------------------------------------------------*/
int main(void)
{
  /* USER CODE BEGIN 1 */
 
  /* USER CODE END 1 */
 
  HAL_Init();
 
  SystemClock_Config();
 
  MX_GPIO_Init();
  MX_SPI1_Init();
  /* USER CODE BEGIN 2 */
 
  AD5940_Initialize();
 
  uint32_t j = AD5940_ReadReg(REG_AFECON_CHIPID);
  /* USER CODE END 2 */
 
  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
  }
}
 
void SystemClock_Config(void)
{
  RCC_OscInitTypeDef RCC_OscInitStruct = {0};
  RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};
 
  /** Configure the main internal regulator output voltage
  */
  __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);
 
  /** Initializes the RCC Oscillators according to the specified parameters
  * in the RCC_OscInitTypeDef structure.
  */
  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI|RCC_OSCILLATORTYPE_HSE
                              |RCC_OSCILLATORTYPE_MSI;
  RCC_OscInitStruct.HSEState = RCC_HSE_ON;
  RCC_OscInitStruct.HSIState = RCC_HSI_ON;
  RCC_OscInitStruct.MSIState = RCC_MSI_ON;
  RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;
  RCC_OscInitStruct.MSICalibrationValue = RCC_MSICALIBRATION_DEFAULT;
  RCC_OscInitStruct.MSIClockRange = RCC_MSIRANGE_10;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_NONE;
  if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
  {
    Error_Handler();
  }
 
  /** Configure the SYSCLKSource, HCLK, PCLK1 and PCLK2 clocks dividers
  */
  RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK4|RCC_CLOCKTYPE_HCLK2
                              |RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
                              |RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;
  RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_MSI;
  RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
  RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;
  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;
  RCC_ClkInitStruct.AHBCLK2Divider = RCC_SYSCLK_DIV1;
  RCC_ClkInitStruct.AHBCLK4Divider = RCC_SYSCLK_DIV1;
 
  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_1) != HAL_OK)
  {
    Error_Handler();
  }
  HAL_RCC_MCOConfig(RCC_MCO1, RCC_MCO1SOURCE_SYSCLK, RCC_MCODIV_1);
}
 
/**
  * @brief Peripherals Common Clock Configuration
  * @retval None
  */
void PeriphCommonClock_Config(void)
{
  RCC_PeriphCLKInitTypeDef PeriphClkInitStruct = {0};
 
  /** Initializes the peripherals clock
  */
  PeriphClkInitStruct.PeriphClockSelection = RCC_PERIPHCLK_SMPS;
  PeriphClkInitStruct.SmpsClockSelection = RCC_SMPSCLKSOURCE_HSI;
  PeriphClkInitStruct.SmpsDivSelection = RCC_SMPSCLKDIV_RANGE0;
 
  if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInitStruct) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN Smps */
 
  /* USER CODE END Smps */
}
 
/**
  * @brief SPI1 Initialization Function
  * @param None
  * @retval None
  */
static void MX_SPI1_Init(void)
{
 
  /* USER CODE BEGIN SPI1_Init 0 */
 
  /* USER CODE END SPI1_Init 0 */
 
  /* USER CODE BEGIN SPI1_Init 1 */
 
  /* USER CODE END SPI1_Init 1 */
  /* SPI1 parameter configuration*/
  hspi1.Instance = SPI1;
  hspi1.Init.Mode = SPI_MODE_MASTER;
  hspi1.Init.Direction = SPI_DIRECTION_2LINES;
  hspi1.Init.DataSize = SPI_DATASIZE_8BIT;
  hspi1.Init.CLKPolarity = SPI_POLARITY_LOW;
  hspi1.Init.CLKPhase = SPI_PHASE_1EDGE;
  hspi1.Init.NSS = SPI_NSS_SOFT;
  hspi1.Init.BaudRatePrescaler = SPI_BAUDRATEPRESCALER_16;
  hspi1.Init.FirstBit = SPI_FIRSTBIT_MSB;
  hspi1.Init.TIMode = SPI_TIMODE_DISABLE;
  hspi1.Init.CRCCalculation = SPI_CRCCALCULATION_DISABLE;
  hspi1.Init.CRCPolynomial = 7;
  hspi1.Init.CRCLength = SPI_CRC_LENGTH_DATASIZE;
  hspi1.Init.NSSPMode = SPI_NSS_PULSE_ENABLE;
  if (HAL_SPI_Init(&hspi1) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN SPI1_Init 2 */
 
  /* USER CODE END SPI1_Init 2 */
 
}
 
/**
  * @brief GPIO Initialization Function
  * @param None
  * @retval None
  */
static void MX_GPIO_Init(void)
{
  GPIO_InitTypeDef GPIO_InitStruct = {0};
 
  /* GPIO Ports Clock Enable */
  __HAL_RCC_GPIOC_CLK_ENABLE();
  __HAL_RCC_GPIOA_CLK_ENABLE();
  __HAL_RCC_GPIOB_CLK_ENABLE();
  __HAL_RCC_GPIOD_CLK_ENABLE();
 
  /*Configure GPIO pin Output Level */
  HAL_GPIO_WritePin(SPI_CS_GPIO_Port, SPI_CS_Pin, GPIO_PIN_SET);
 
  /*Configure GPIO pin Output Level */
  HAL_GPIO_WritePin(SPI_RST_GPIO_Port, SPI_RST_Pin, GPIO_PIN_RESET);
 
  /*Configure GPIO pin Output Level */
  HAL_GPIO_WritePin(GPIOB, LD2_Pin|LD3_Pin|LD1_Pin, GPIO_PIN_RESET);
 
  /*Configure GPIO pins : SPI_CS_Pin SPI_RST_Pin */
  GPIO_InitStruct.Pin = SPI_CS_Pin|SPI_RST_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
 
  /*Configure GPIO pin : PA8 */
  GPIO_InitStruct.Pin = GPIO_PIN_8;
  GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  GPIO_InitStruct.Alternate = GPIO_AF0_MCO;
  HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
 
  /*Configure GPIO pin : B1_Pin */
  GPIO_InitStruct.Pin = B1_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  HAL_GPIO_Init(B1_GPIO_Port, &GPIO_InitStruct);
 
  /*Configure GPIO pins : LD2_Pin LD3_Pin LD1_Pin */
  GPIO_InitStruct.Pin = LD2_Pin|LD3_Pin|LD1_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);
 
  /*Configure GPIO pins : PA11 PA12 */
  GPIO_InitStruct.Pin = GPIO_PIN_11|GPIO_PIN_12;
  GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  GPIO_InitStruct.Alternate = GPIO_AF10_USB;
  HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
 
  /*Configure GPIO pins : B2_Pin B3_Pin */
  GPIO_InitStruct.Pin = B2_Pin|B3_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  HAL_GPIO_Init(GPIOD, &GPIO_InitStruct);
 
  /*Configure GPIO pins : STLINK_RX_Pin STLINK_TX_Pin */
  GPIO_InitStruct.Pin = STLINK_RX_Pin|STLINK_TX_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  GPIO_InitStruct.Alternate = GPIO_AF7_USART1;
  HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);
 
}
 
/* USER CODE BEGIN 4 */
 
 
void HAL_SPI_TxRxCpltCallback(SPI_HandleTypeDef *hspi)
{
  /* Prevent unused argument(s) compilation warning */
  UNUSED(hspi);
 
  /* NOTE : This function should not be modified, when the callback is needed,
            the HAL_SPI_TxRxCpltCallback should be implemented in the user file
   */
}
 
volatile static uint8_t ucInterrupted = 0;       /* Flag to indicate interrupt occurred */
 
/**
	@brief Using SPI to transmit N bytes and return the received bytes. This function targets to
                     provide a more efficent way to transmit/receive data.
	@param pSendBuffer :{0 - 0xFFFFFFFF}
      - Pointer to the data to be sent.
	@param pRecvBuff :{0 - 0xFFFFFFFF}
      - Pointer to the buffer used to store received data.
	@param length :{0 - 0xFFFFFFFF}
      - Data length in SendBuffer.
	@return None.
**/
void AD5940_ReadWriteNBytes(unsigned char *pSendBuffer,unsigned char *pRecvBuff,unsigned long length)
{
  HAL_SPI_TransmitReceive_IT(&hspi1, pSendBuffer, pRecvBuff, length);
 
  // Wait for SPI transfer to complete
  while (HAL_SPI_GetState(&hspi1) != HAL_SPI_STATE_READY);
}
 
void AD5940_CsClr(void)
{
  HAL_GPIO_WritePin(SPI_CS_GPIO_Port, SPI_CS_Pin, GPIO_PIN_RESET);
}
 
void AD5940_CsSet(void)
{
 
  HAL_GPIO_WritePin(SPI_CS_GPIO_Port, SPI_CS_Pin, GPIO_PIN_SET);
}
 
void AD5940_RstSet(void)
{
  HAL_GPIO_WritePin(SPI_RST_GPIO_Port, SPI_RST_Pin, GPIO_PIN_SET);
}
 
void AD5940_RstClr(void)
{
  HAL_GPIO_WritePin(SPI_RST_GPIO_Port, SPI_RST_Pin, GPIO_PIN_RESET);
}
 
void AD5940_Delay10us(uint32_t time)
{
  time/=100;
  if(time == 0) time =1;
  HAL_Delay(time*8);
}
 
uint32_t AD5940_GetMCUIntFlag(void)
{
	return ucInterrupted;
}
/* USER CODE END 4 */
 

Main.c file . Please reach out to me if any further information is reuired.

[waclawek.jan]

> When projecting the MISO line on the digital analyzer, observing the miso line stays high always.

Disconnect MISO from STM32. Still always high? Then the problem is at the slave's side: this signal is output from the slave.

Observe and compare waveforms of input signals to slave (MOSI, SCK, any chipselect/slave select (CS/SS) pin) with description in the slave's datasheet.

JW