STM32 SPI总线结构

一：SPI总线是什么

SPI英文名为Serial Peripheral Interface翻译成中文为串行外设接口，适用于高速、双向数据传输场景。

二：SPI总线的结构

SPI总线可以与大量的从机相连接。

SPI主机最少有4个引脚，分别为MOSI，MISO，SCK，NSS1.

MOSI ：为Master Output Slave Input的缩写，中文解释为主机输出从机输入。规则是低电压表示0高电压表示1。

MISO：为Master Input Slave output的缩写，中文解释为主机输入从机输出，规则与MOSI一样。

SCK：Serial Clock，中文解释为串行时钟线，时钟信号一般由主机发出。

NSS：Negative Slave Select，中文解释为从机选择（低电压有效），主机向对应的NSS发送低电压可以选中从机。

以下为主机与从机相连接的小总结：

三：SPI的五个参数

SPI参数由波特率，比特位传输顺序（MSB First/LSB First），数据为长度（8位/16位），时钟的极性，时钟的相位，这五个参数所决定。

1、波特率

2、比特位传输顺序（MSB First/LSB First）

3、数据位的长度

4、时钟的极性

5、时钟的相位

6、时钟的四种模式

有了时钟的极性和时钟的相位我们可以得到时钟的四种模式：

四：外部flash实验

应用到的有STM32F103c8t6作为核心板，W25QXX 为flash模块，和外接按键用来切换板载led灯的状态，并将状态存放到W25Qxx模块中。

将PC13引脚设置为GPIO_Output ,用于点亮led灯，GPIO_Input ，用于按键输入，PA4引脚作为主机片选从机信号，PA5，PA6，PA7为SPI通信相关引脚。SPI通信配置如下

1、接线图如下：

2、SPI，HAL库常用的几种函数

3、W25Q64的结构

4、Flash数据写入过程

5、W25Q64的写使能代码

6、W25Q64的扇区擦除

7、W25Q64的页编程

8、W25Q64返回数据编程

9、main函数代码如下

/* 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"

/* 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 */

/* 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);
static void MX_GPIO_Init(void);
static void MX_SPI1_Init(void);
static void SaveLEDState(uint8_t ledstate);
static uint8_t ReadLEDState(void);
/* USER CODE BEGIN PFP */

/* USER CODE END PFP */

/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */
static void SaveLEDState(uint8_t ledstate)
{
	//#1.写使能
	uint8_t writeEnablecmd[]={0x06};
	HAL_GPIO_WritePin(GPIOA,GPIO_PIN_4,GPIO_PIN_RESET);
	HAL_SPI_Transmit(
		&hspi1,
		writeEnablecmd,
		1,
		HAL_MAX_DELAY
	);
	HAL_GPIO_WritePin(GPIOA,GPIO_PIN_4,GPIO_PIN_SET);
	//#2.扇区擦除
	uint8_t sectorEraseCmd[]={0x20,0x00,0x00,0x00};
	HAL_GPIO_WritePin(GPIOA,GPIO_PIN_4,GPIO_PIN_RESET);
	HAL_SPI_Transmit(&hspi1,sectorEraseCmd,4,HAL_MAX_DELAY);
	HAL_GPIO_WritePin(GPIOA,GPIO_PIN_4,GPIO_PIN_SET);
	
	HAL_Delay(100);
	//#3.写使能
	HAL_GPIO_WritePin(GPIOA,GPIO_PIN_4,GPIO_PIN_RESET);
	HAL_SPI_Transmit(
		&hspi1,
		writeEnablecmd,
		1,
		HAL_MAX_DELAY
	);
	HAL_GPIO_WritePin(GPIOA,GPIO_PIN_4,GPIO_PIN_SET);
	//#4.页编程
	uint8_t pageProgCmd[5];
	pageProgCmd[0]=0x02;//指令码
	pageProgCmd[1]=pageProgCmd[2]=pageProgCmd[3]=0x00;
	pageProgCmd[4]=ledstate;//要写入的数据（led的状态）
	HAL_GPIO_WritePin(GPIOA,GPIO_PIN_4,GPIO_PIN_RESET);
	HAL_SPI_Transmit(&hspi1,pageProgCmd,5,HAL_MAX_DELAY);
	HAL_GPIO_WritePin(GPIOA,GPIO_PIN_4,GPIO_PIN_SET);
	
	HAL_Delay(10);
}

static uint8_t ReadLEDState()
{
	uint8_t readDataCmd[]={0x03,0x00,0x00,0x00};
	uint8_t ledstate;//用于接收读出的数据
	HAL_GPIO_WritePin(GPIOA,GPIO_PIN_4,GPIO_PIN_RESET);
	HAL_SPI_Transmit(&hspi1,readDataCmd,4,HAL_MAX_DELAY);
	HAL_SPI_Receive(&hspi1,&ledstate,1,HAL_MAX_DELAY);
	HAL_GPIO_WritePin(GPIOA,GPIO_PIN_4,GPIO_PIN_SET);
	return ledstate;
	
}
/* 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_SPI1_Init();
  /* USER CODE BEGIN 2 */

  /* USER CODE END 2 */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  uint8_t pre=1,cur=1;
  uint8_t led_state=0;
  led_state=ReadLEDState();
  if(led_state==0)//为灭
	  HAL_GPIO_WritePin(GPIOC,GPIO_PIN_13,GPIO_PIN_SET);
  else 
	  HAL_GPIO_WritePin(GPIOC,GPIO_PIN_13,GPIO_PIN_RESET);
  while (1)
  {	pre=cur;
	 if(HAL_GPIO_ReadPin(GPIOC,GPIO_PIN_14)==GPIO_PIN_SET)
		 cur=1;
	 else cur=0;
	 HAL_Delay(10);
	 if(pre!=cur)
	 {
		 if(cur==0){}//为按键按下状态
			 else//为按键松开状态
		{
			if(led_state==0)//为灭的状态将其翻转为点亮的状态
			{
			HAL_GPIO_WritePin(GPIOC,GPIO_PIN_13,GPIO_PIN_RESET);
			led_state=1;
			}
			else //为亮的状态将其翻转为熄灭的状态
			{
			HAL_GPIO_WritePin(GPIOC,GPIO_PIN_13,GPIO_PIN_SET);
			led_state=0;
			}
			SaveLEDState(led_state);
		}
	 }
    /* 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};

  /** Initializes the RCC Oscillators according to the specified parameters
  * in the RCC_OscInitTypeDef structure.
  */
  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI;
  RCC_OscInitStruct.HSIState = RCC_HSI_ON;
  RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_NONE;
  if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != 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_HSI;
  RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
  RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;
  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;

  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_0) != HAL_OK)
  {
    Error_Handler();
  }
}

/**
  * @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_HIGH;
  hspi1.Init.CLKPhase = SPI_PHASE_2EDGE;
  hspi1.Init.NSS = SPI_NSS_SOFT;
  hspi1.Init.BaudRatePrescaler = SPI_BAUDRATEPRESCALER_8;
  hspi1.Init.FirstBit = SPI_FIRSTBIT_MSB;
  hspi1.Init.TIMode = SPI_TIMODE_DISABLE;
  hspi1.Init.CRCCalculation = SPI_CRCCALCULATION_DISABLE;
  hspi1.Init.CRCPolynomial = 10;
  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};
/* USER CODE BEGIN MX_GPIO_Init_1 */
/* USER CODE END MX_GPIO_Init_1 */

  /* GPIO Ports Clock Enable */
  __HAL_RCC_GPIOC_CLK_ENABLE();
  __HAL_RCC_GPIOA_CLK_ENABLE();

  /*Configure GPIO pin Output Level */
  HAL_GPIO_WritePin(GPIOC, GPIO_PIN_13, GPIO_PIN_SET);

  /*Configure GPIO pin Output Level */
  HAL_GPIO_WritePin(GPIOA, GPIO_PIN_4, GPIO_PIN_SET);

  /*Configure GPIO pin : PC13 */
  GPIO_InitStruct.Pin = GPIO_PIN_13;
  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_OD;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  HAL_GPIO_Init(GPIOC, &GPIO_InitStruct);

  /*Configure GPIO pin : PC14 */
  GPIO_InitStruct.Pin = GPIO_PIN_14;
  GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
  GPIO_InitStruct.Pull = GPIO_PULLUP;
  HAL_GPIO_Init(GPIOC, &GPIO_InitStruct);

  /*Configure GPIO pin : PA4 */
  GPIO_InitStruct.Pin = GPIO_PIN_4;
  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;
  HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

/* USER CODE BEGIN MX_GPIO_Init_2 */
/* USER CODE END MX_GPIO_Init_2 */
}

/* USER CODE BEGIN 4 */

/* 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.
  * @param  file: pointer to the source file name
  * @param  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 */

作者：几许_