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 */