DMA Circular mode misalignment

[g_timp]

Hi everyone!

I'm trying to figure out what's wrong with my SPI Peripheral continous transmitting/receiving via DMA in Circular Mode. I think I have coded a pretty basic "Hello, World" for working with DMA, I've just generated code from .ioc file and then added a simple logic. This is my main.c:

/* USER CODE BEGIN Header */
/**
  ******************************************************************************
  * @file           : main.c
  * @brief          : Main program body
  ******************************************************************************
  * @attention
  *
  * Copyright (c) 2025 STMicroelectronics.
  * All rights reserved.
  *
  * This software is licensed under terms that can be found in the LICENSE file
  * in the root directory of this software component.
  * If no LICENSE file comes with this software, it is provided AS-IS.
  *
  ******************************************************************************
  */
/* USER CODE END Header */
/* Includes ------------------------------------------------------------------*/
#include "main.h"
#include "dma.h"
#include "spi.h"
#include "usart.h"
#include "usb_otg.h"
#include "gpio.h"

/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */

/* USER CODE END Includes */

/* Private typedef -----------------------------------------------------------*/
/* USER CODE BEGIN PTD */

/* USER CODE END PTD */

/* Private define ------------------------------------------------------------*/
/* USER CODE BEGIN PD */
#define SPI3_BUFFER_SIZE 2

/* USER CODE END PD */

/* Private macro -------------------------------------------------------------*/
/* USER CODE BEGIN PM */

/* USER CODE END PM */

/* Private variables ---------------------------------------------------------*/

/* USER CODE BEGIN PV */
volatile uint8_t spi3_tx_buffer[SPI3_BUFFER_SIZE] = {0};
volatile uint8_t spi3_rx_buffer[SPI3_BUFFER_SIZE] = {0};

/* USER CODE END PV */

/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
/* USER CODE BEGIN PFP */
void SPI3_Start_Comm(void);

/* USER CODE END PFP */

/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */

/* USER CODE END 0 */

/**
  * @brief  The application entry point.
  * @retval int
  */
int main(void)
{

  /* USER CODE BEGIN 1 */

  /* USER CODE END 1 */

  /* MCU Configuration--------------------------------------------------------*/

  /* Reset of all peripherals, Initializes the Flash interface and the Systick. */
  HAL_Init();

  /* USER CODE BEGIN Init */

  /* USER CODE END Init */

  /* Configure the system clock */
  SystemClock_Config();

  /* USER CODE BEGIN SysInit */

  /* USER CODE END SysInit */

  /* Initialize all configured peripherals */
  MX_GPIO_Init();
  MX_DMA_Init();
  MX_USART3_UART_Init();
  MX_USB_OTG_FS_PCD_Init();
  MX_SPI3_Init();
  /* USER CODE BEGIN 2 */

  SPI3_Start_Comm();

  /* USER CODE END 2 */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
    /* USER CODE END WHILE */

    /* USER CODE BEGIN 3 */
  }
  /* USER CODE END 3 */
}

/**
  * @brief System Clock Configuration
  * @retval None
  */
void SystemClock_Config(void)
{
  RCC_OscInitTypeDef RCC_OscInitStruct = {0};
  RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};

  /** Configure LSE Drive Capability
  */
  HAL_PWR_EnableBkUpAccess();

  /** Configure the main internal regulator output voltage
  */
  __HAL_RCC_PWR_CLK_ENABLE();
  __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_HSE;
  RCC_OscInitStruct.HSEState = RCC_HSE_BYPASS;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
  RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
  RCC_OscInitStruct.PLL.PLLM = 4;
  RCC_OscInitStruct.PLL.PLLN = 216;
  RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;
  RCC_OscInitStruct.PLL.PLLQ = 9;
  if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
  {
    Error_Handler();
  }

  /** Activate the Over-Drive mode
  */
  if (HAL_PWREx_EnableOverDrive() != HAL_OK)
  {
    Error_Handler();
  }

  /** Initializes the CPU, AHB and APB buses clocks
  */
  RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
                              |RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;
  RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
  RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
  RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV4;
  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV2;

  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_7) != HAL_OK)
  {
    Error_Handler();
  }
}

/* USER CODE BEGIN 4 */

/**
 * @brief This function starts SPI Communication for Peripheral device
 * @retval None
 */
void SPI3_Start_Comm(void)
{
	HAL_SPI_TransmitReceive_DMA(&hspi3,(uint8_t*)spi3_tx_buffer,
			(uint8_t*)spi3_rx_buffer,SPI3_BUFFER_SIZE);
}

void HAL_SPI_TxRxCpltCallback(SPI_HandleTypeDef *hspi)
{

	if(hspi->Instance == SPI3)
	{
		spi3_tx_buffer[0] = spi3_rx_buffer[0];
		spi3_tx_buffer[1] = spi3_rx_buffer[1];
	}

}

/* USER CODE END 4 */

/**
  * @brief  This function is executed in case of error occurrence.
  * @retval None
  */
void Error_Handler(void)
{
  /* USER CODE BEGIN Error_Handler_Debug */
  /* User can add his own implementation to report the HAL error return state */
  __disable_irq();
  while (1)
  {
  }
  /* USER CODE END Error_Handler_Debug */
}

#ifdef  USE_FULL_ASSERT
/**
  * @brief  Reports the name of the source file and the source line number
  *         where the assert_param error has occurred.
  *   file: pointer to the source file name
  *   line: assert_param error line source number
  * @retval None
  */
void assert_failed(uint8_t *file, uint32_t line)
{
  /* USER CODE BEGIN 6 */
  /* User can add his own implementation to report the file name and line number,
     ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
  /* USER CODE END 6 */
}
#endif /* USE_FULL_ASSERT */

As you can see, I just start communication in SPI3_Start_Comm() and then in HAL_SPI_TxRxCpltCallback I prepare the bytes received at N-time to echo back at N+1-time.

What I get is the peripheral echoing back bytes at N+x-time, after three or four garbage results at first. If I print results from controller point of view this is what I get:

    COPI CIPO
0: 0000 XXXX (garbage)
1: 0000 XXXX (garbage)
2: 0800 XXXX (garbage)
3: 0800 XXXX (garbage)
4: 1000 0000 (N+3 echo back - it should be N+1 or 0800). Missing N = 0 echo
5: 1000 0800 (and so on...)
6: 1800 0800
7: 1800 1000
8: 2000 1000
9: 2000 1800
10: 2800 1800
11: 2800 2000
12: 3000 2000
13: 3000 2800
14: 3800 2800
15: 3800 3000
16: 0000 3000
17: 0000 3800
18: 0800 3800
19: 0800 0000
20: 1000 0000
...

Peripheral device is STM32F722ZE. Controller is a black box.

Here's my spi.c and dma.c files generated from .ioc:

spi.c:

/* USER CODE BEGIN Header */
/**
  ******************************************************************************
  * @file    spi.c
  * @brief   This file provides code for the configuration
  *          of the SPI instances.
  ******************************************************************************
  * @attention
  *
  * Copyright (c) 2025 STMicroelectronics.
  * All rights reserved.
  *
  * This software is licensed under terms that can be found in the LICENSE file
  * in the root directory of this software component.
  * If no LICENSE file comes with this software, it is provided AS-IS.
  *
  ******************************************************************************
  */
/* USER CODE END Header */
/* Includes ------------------------------------------------------------------*/
#include "spi.h"

/* USER CODE BEGIN 0 */

/* USER CODE END 0 */

SPI_HandleTypeDef hspi3;
DMA_HandleTypeDef hdma_spi3_rx;
DMA_HandleTypeDef hdma_spi3_tx;

/* SPI3 init function */
void MX_SPI3_Init(void)
{

  /* USER CODE BEGIN SPI3_Init 0 */

  /* USER CODE END SPI3_Init 0 */

  /* USER CODE BEGIN SPI3_Init 1 */

  /* USER CODE END SPI3_Init 1 */
  hspi3.Instance = SPI3;
  hspi3.Init.Mode = SPI_MODE_SLAVE;
  hspi3.Init.Direction = SPI_DIRECTION_2LINES;
  hspi3.Init.DataSize = SPI_DATASIZE_8BIT;
  hspi3.Init.CLKPolarity = SPI_POLARITY_HIGH;
  hspi3.Init.CLKPhase = SPI_PHASE_2EDGE;
  hspi3.Init.NSS = SPI_NSS_HARD_INPUT;
  hspi3.Init.FirstBit = SPI_FIRSTBIT_MSB;
  hspi3.Init.TIMode = SPI_TIMODE_DISABLE;
  hspi3.Init.CRCCalculation = SPI_CRCCALCULATION_DISABLE;
  hspi3.Init.CRCPolynomial = 7;
  hspi3.Init.CRCLength = SPI_CRC_LENGTH_DATASIZE;
  hspi3.Init.NSSPMode = SPI_NSS_PULSE_DISABLE;
  if (HAL_SPI_Init(&hspi3) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN SPI3_Init 2 */

  /* USER CODE END SPI3_Init 2 */

}

void HAL_SPI_MspInit(SPI_HandleTypeDef* spiHandle)
{

  GPIO_InitTypeDef GPIO_InitStruct = {0};
  if(spiHandle->Instance==SPI3)
  {
  /* USER CODE BEGIN SPI3_MspInit 0 */

  /* USER CODE END SPI3_MspInit 0 */
    /* SPI3 clock enable */
    __HAL_RCC_SPI3_CLK_ENABLE();

    __HAL_RCC_GPIOA_CLK_ENABLE();
    __HAL_RCC_GPIOB_CLK_ENABLE();
    /**SPI3 GPIO Configuration
    PA4     ------> SPI3_NSS
    PB3     ------> SPI3_SCK
    PB4     ------> SPI3_MISO
    PB5     ------> SPI3_MOSI
    */
    GPIO_InitStruct.Pin = GPIO_PIN_4;
    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
    GPIO_InitStruct.Pull = GPIO_NOPULL;
    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
    GPIO_InitStruct.Alternate = GPIO_AF6_SPI3;
    HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

    GPIO_InitStruct.Pin = GPIO_PIN_3|GPIO_PIN_4|GPIO_PIN_5;
    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
    GPIO_InitStruct.Pull = GPIO_NOPULL;
    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
    GPIO_InitStruct.Alternate = GPIO_AF6_SPI3;
    HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);

    /* SPI3 DMA Init */
    /* SPI3_RX Init */
    hdma_spi3_rx.Instance = DMA1_Stream0;
    hdma_spi3_rx.Init.Channel = DMA_CHANNEL_0;
    hdma_spi3_rx.Init.Direction = DMA_PERIPH_TO_MEMORY;
    hdma_spi3_rx.Init.PeriphInc = DMA_PINC_DISABLE;
    hdma_spi3_rx.Init.MemInc = DMA_MINC_ENABLE;
    hdma_spi3_rx.Init.PeriphDataAlignment = DMA_PDATAALIGN_BYTE;
    hdma_spi3_rx.Init.MemDataAlignment = DMA_MDATAALIGN_BYTE;
    hdma_spi3_rx.Init.Mode = DMA_CIRCULAR;
    hdma_spi3_rx.Init.Priority = DMA_PRIORITY_VERY_HIGH;
    hdma_spi3_rx.Init.FIFOMode = DMA_FIFOMODE_DISABLE;
    if (HAL_DMA_Init(&hdma_spi3_rx) != HAL_OK)
    {
      Error_Handler();
    }

    __HAL_LINKDMA(spiHandle,hdmarx,hdma_spi3_rx);

    /* SPI3_TX Init */
    hdma_spi3_tx.Instance = DMA1_Stream5;
    hdma_spi3_tx.Init.Channel = DMA_CHANNEL_0;
    hdma_spi3_tx.Init.Direction = DMA_MEMORY_TO_PERIPH;
    hdma_spi3_tx.Init.PeriphInc = DMA_PINC_DISABLE;
    hdma_spi3_tx.Init.MemInc = DMA_MINC_ENABLE;
    hdma_spi3_tx.Init.PeriphDataAlignment = DMA_PDATAALIGN_BYTE;
    hdma_spi3_tx.Init.MemDataAlignment = DMA_MDATAALIGN_BYTE;
    hdma_spi3_tx.Init.Mode = DMA_CIRCULAR;
    hdma_spi3_tx.Init.Priority = DMA_PRIORITY_VERY_HIGH;
    hdma_spi3_tx.Init.FIFOMode = DMA_FIFOMODE_DISABLE;
    if (HAL_DMA_Init(&hdma_spi3_tx) != HAL_OK)
    {
      Error_Handler();
    }

    __HAL_LINKDMA(spiHandle,hdmatx,hdma_spi3_tx);

    /* SPI3 interrupt Init */
    HAL_NVIC_SetPriority(SPI3_IRQn, 0, 0);
    HAL_NVIC_EnableIRQ(SPI3_IRQn);
  /* USER CODE BEGIN SPI3_MspInit 1 */

  /* USER CODE END SPI3_MspInit 1 */
  }
}

void HAL_SPI_MspDeInit(SPI_HandleTypeDef* spiHandle)
{

  if(spiHandle->Instance==SPI3)
  {
  /* USER CODE BEGIN SPI3_MspDeInit 0 */

  /* USER CODE END SPI3_MspDeInit 0 */
    /* Peripheral clock disable */
    __HAL_RCC_SPI3_CLK_DISABLE();

    /**SPI3 GPIO Configuration
    PA4     ------> SPI3_NSS
    PB3     ------> SPI3_SCK
    PB4     ------> SPI3_MISO
    PB5     ------> SPI3_MOSI
    */
    HAL_GPIO_DeInit(GPIOA, GPIO_PIN_4);

    HAL_GPIO_DeInit(GPIOB, GPIO_PIN_3|GPIO_PIN_4|GPIO_PIN_5);

    /* SPI3 DMA DeInit */
    HAL_DMA_DeInit(spiHandle->hdmarx);
    HAL_DMA_DeInit(spiHandle->hdmatx);

    /* SPI3 interrupt Deinit */
    HAL_NVIC_DisableIRQ(SPI3_IRQn);
  /* USER CODE BEGIN SPI3_MspDeInit 1 */

  /* USER CODE END SPI3_MspDeInit 1 */
  }
}

/* USER CODE BEGIN 1 */

/* USER CODE END 1 */

dma.c:

/* USER CODE BEGIN Header */
/**
  ******************************************************************************
  * @file    dma.c
  * @brief   This file provides code for the configuration
  *          of all the requested memory to memory DMA transfers.
  ******************************************************************************
  * @attention
  *
  * Copyright (c) 2025 STMicroelectronics.
  * All rights reserved.
  *
  * This software is licensed under terms that can be found in the LICENSE file
  * in the root directory of this software component.
  * If no LICENSE file comes with this software, it is provided AS-IS.
  *
  ******************************************************************************
  */
/* USER CODE END Header */

/* Includes ------------------------------------------------------------------*/
#include "dma.h"

/* USER CODE BEGIN 0 */

/* USER CODE END 0 */

/*----------------------------------------------------------------------------*/
/* Configure DMA                                                              */
/*----------------------------------------------------------------------------*/

/* USER CODE BEGIN 1 */

/* USER CODE END 1 */

/**
  * Enable DMA controller clock
  */
void MX_DMA_Init(void)
{

  /* DMA controller clock enable */
  __HAL_RCC_DMA1_CLK_ENABLE();

  /* DMA interrupt init */
  /* DMA1_Stream0_IRQn interrupt configuration */
  HAL_NVIC_SetPriority(DMA1_Stream0_IRQn, 0, 0);
  HAL_NVIC_EnableIRQ(DMA1_Stream0_IRQn);
  /* DMA1_Stream1_IRQn interrupt configuration */
  HAL_NVIC_SetPriority(DMA1_Stream1_IRQn, 0, 0);
  HAL_NVIC_EnableIRQ(DMA1_Stream1_IRQn);
  /* DMA1_Stream3_IRQn interrupt configuration */
  HAL_NVIC_SetPriority(DMA1_Stream3_IRQn, 0, 0);
  HAL_NVIC_EnableIRQ(DMA1_Stream3_IRQn);
  /* DMA1_Stream5_IRQn interrupt configuration */
  HAL_NVIC_SetPriority(DMA1_Stream5_IRQn, 0, 0);
  HAL_NVIC_EnableIRQ(DMA1_Stream5_IRQn);

}

/* USER CODE BEGIN 2 */

/* USER CODE END 2 */

What am I missing?

Thanks to anyone who will try to help!

[g_timp]

From RM0431:
"While the master can provide all the transactions in continuous mode (SCK signal is
continuous) it has to respect slave capability to handle data flow and its content at anytime.
When necessary, the master must slow down the communication and provide either a
slower clock or separate frames or data sessions with sufficient delays. Be aware there is no
underflow error signal for master or slave in SPI mode, and data from the slave is always
transacted and processed by the master even if the slave could not prepare it correctly in
time. It is preferable for the slave to use DMA, especially when data frames are shorter and
bus rate is high."

[TDK]

I don't feel like we're getting anywhere. I agree with what the RM is saying and am not contradicting it. You should be using DMA here.

[MasterT]

---

@g_timp wrote:

MasterT: thanks but I was looking for a far simpler code for this purpose.

Let me reformulate my question: how would you program a SPI Peripheral for continuously receiving data from a black box controller and echoing data back, such as when Controller sends N+1 data Peripheral responds with N data?

I'd programm SPI as a slave 2-lines just for receiving data on stm32 end.

To echo back the same unaltered data, I'd jump Tx-Rx pins at the transmitter side (black box or whatever), so transmitter always has  a copy of it's own byte one transaction later N+1. 

What for, is it exercise some kind?

[g_timp]

Echoing back will be replaced by getting a result from a lookup table, I was just moving the very first step (I called it a "Hello, World" of using DMA to continuously transmitting/receving data from a SPI peripheral).

[MasterT]

If data altered, than you can't make it fast, since DMA is out of scope.

2 usec interrupts load F7 to about 100%.