想实现断电保存少量的一些数据，stm32内部flash 排除运行程序占用空间后，还有剩余空间，可以把这些空间利用起来。
在操作前，推荐先看一下flash 存储 页、扇区、块概念和flash 每页地址,推荐： https://blog.csdn.net/ybhuangfugui/article/details/121463317
如果只是单纯想存、取数据，那就只关注页、每页大小、每页开始地址就可以了。
stm32f103c6t6 共 32 页， 每页 1kb(1024字节)，也就是说，有32kb的断电保存空间,减去运行程序占用空间，剩下的，都是可操作空间。
涉及到基本感念:
8bit = 1b(byte 字节), 1024kb = 1Mb
uint8_t类型 占用 8bit(1b)
uint16_t类型 占用 16bit(2b)
uint32_t类型 占用 32bit(4b)
uint64_t类型 占用 64bit(8b)
第一页开始地址: 0x8000000 结束地址： 0x80003FF
此处可以打开计算器试着计算一下:
获取运行程序实际大小:
在keil5中，执行rebuild, 完成后在结果中找到:
把这几个值加起来，除1024(值的单位是b(byte))： 4244 + 292 + 16 + 1128 = 5680 ; 5680 / 1024 = 5.54kb,相当于程序占用了5页半，就当六页算。
在操作flash存储数据时，为防止影响到程序代码，可以隔一页，写数据。从第七页开始存储,(不一定必须隔一页，只是个人习惯)
0x8000000 + (1024 * 6) = 0x8001800
此处乘 6不是 乘7,是因为页是从0开始的，0页地址是0x8000000，1页就是 0x8000000 + (1024) ,2页就是 0x8000000 + (1024 * 2).....
比如存储一个uint16_t类型数据,因为uint16_t占2字节,所以,0x8001800 + 2 = 0x8001802，这个变量内容就存储在:0x8001801和0x8001802两个地址中。
以下是我写的测试代码方法，测试存取数据操作:
#define PAGE_START_ADDRESS 0x8000000
//paramSizeKb 程序大小 //data 准备写入数据 //len 大小 bool flashWriteData(int paramSizeKb, uint64_t data[], size_t len) { HAL_FLASH_Unlock();//解锁flash //准备擦除整页,写入前需要擦除 FLASH_EraseInitTypeDef f; f.TypeErase = FLASH_TYPEERASE_PAGES;//页擦除 f.PageAddress = PAGE_START_ADDRESS + (1024 * paramSizeKb);//擦除页地址 f.NbPages = 1;//擦除1页 uint32_t PageError = 0; HAL_FLASHEx_Erase(&f, &PageError);//擦除PageError == 0xFFFFFFFF表示成功 if(PageError != 0xFFFFFFFF) { return false; } //开始写数据 uint32_t startAddressIndex = PAGE_START_ADDRESS + (1024 * paramSizeKb); //startAddressIndex += 8,写入位置，每次+8是因为存储的类型是uint64_t,占用64bit,8字节 for(int i = 0 ; i < len;i ++ , startAddressIndex += 8) { //写入数据 HAL_FLASH_Program(FLASH_TYPEPROGRAM_WORD, startAddressIndex, data[i]); } //重新上锁 HAL_FLASH_Lock(); return true; } //读取数据 //paramSizeKb 程序大小 //data 读入数据 //len 读入数据长度 void flashReadData(int paramSizeKb, uint8_t *data, size_t len) { uint32_t startAddressIndex = PAGE_START_ADDRESS + (1024 * paramSizeKb); for(int i = 0; i < len; i++, startAddressIndex += 8){ data[i] = *(__IO uint32_t*)(startAddressIndex); } }
在烧写程序测试前，可以先用keil5 仿真功能测试一下,在测试时需要注意打开指定地址的读写访问操作:
打开运行指定地址读写访问:
首先开启debug调试: Debug -> Start/Stop Debug Session
进入debug调试后，进入Debug -> Memory Map... : Map Range处输入允许读写 开始地址,结束地址,逗号分割; 勾选Read Write复选框，点击Map Range 按钮添加允许读写操作区域。
然后，就可以点击(Run F5)继续调试程序了。
完整测试文件内容main.c:
/* USER CODE BEGIN Header */
/**
******************************************************************************
* @file : main.c
* @brief : Main program body
******************************************************************************
* @attention
*
* <h2><center>© Copyright (c) 2021 STMicroelectronics.
* All rights reserved.</center></h2>
*
* This software component is licensed by ST under BSD 3-Clause license,
* the "License"; You may not use this file except in compliance with the
* License. You may obtain a copy of the License at:
* opensource.org/licenses/BSD-3-Clause
*
******************************************************************************
*/
/* USER CODE END Header */
/* Includes ------------------------------------------------------------------*/
#include "main.h"
#include "usart.h"
#include "gpio.h"
#include "stdbool.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 ---------------------------------------------------------*/
/* USER CODE BEGIN PV */
/* USER CODE END PV */
/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
/* USER CODE BEGIN PFP */
/* USER CODE END PFP */
/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */
/* USER CODE END 0 */
//#define PAGE_START_ADDRESS 0x8000000
#define PAGE_START_ADDRESS 0x8008800
//paramSizeKb 程序大小
//data 准备写入数据
//len 大小
bool flashWriteData(int paramSizeKb, uint64_t data[], size_t len) {
HAL_FLASH_Unlock();//解锁flash
//准备擦除整页,写入前需要擦除
FLASH_EraseInitTypeDef f;
f.TypeErase = FLASH_TYPEERASE_PAGES;//页擦除
f.PageAddress = PAGE_START_ADDRESS + (1024 * paramSizeKb);//擦除页地址
f.NbPages = 1;//擦除1页
uint32_t PageError = 0;
HAL_FLASHEx_Erase(&f, &PageError);//擦除PageError == 0xFFFFFFFF表示成功
if(PageError != 0xFFFFFFFF) {
return false;
}
//开始写数据
uint32_t startAddressIndex = PAGE_START_ADDRESS + (1024 * paramSizeKb);
//startAddressIndex += 8,写入位置，每次+8是因为存储的类型是uint64_t,占用64bit,8字节
for(int i = 0 ; i < len;i ++ , startAddressIndex += 8) {
//写入数据
HAL_FLASH_Program(FLASH_TYPEPROGRAM_WORD, startAddressIndex, data[i]);
}
//重新上锁
HAL_FLASH_Lock();
return true;
}
//读取数据
//paramSizeKb 程序大小
//data 读入数据
//len 读入数据长度
void flashReadData(int paramSizeKb, uint64_t *data, size_t len) {
uint32_t startAddressIndex = PAGE_START_ADDRESS + (1024 * paramSizeKb);
for(int i = 0; i < len; i++, startAddressIndex += 8){
data[i] = *(__IO uint32_t*)(startAddressIndex);
}
}
/**
* @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_USART1_UART_Init();
/* USER CODE BEGIN 2 */
/* USER CODE END 2 */
/* Infinite loop */
/* USER CODE BEGIN WHILE */
//程序大小 6k, rebuild 后 看Program Size: Code=4124 RO-data=292 RW-data=16 ZI-data=1128 ，把这几个数字(byte)加起来 / 1024
//每页1k
while (1)
{
//HAL_UART_Transmit(&huart1, (uint8_t[]){0x00, 0x00, 0x00}, 3, 1000);
/* USER CODE END WHILE */
uint8_t data[3];
if (HAL_UART_Receive(&huart1, data, 3, 100) == HAL_OK) {
//0xAA or 0xBB
uint8_t cmd = 0xFF;
for(int i = 0; i < 3; i++) {
if(data[i] != data[0]) {
HAL_UART_Transmit(&huart1, data, 3, 1000);
break;
}
if (i + 1 == 3) {
cmd = data[0];
}
}
if(cmd == 0xAA) {
uint64_t writeData[5] = {0xAA, 0xBB, 0xCC, 0xDD, 0xEE};
if(flashWriteData(6, writeData, 5)) {
HAL_UART_Transmit(&huart1, (uint8_t[]){0xAA, 0xAA, 0xAA}, 3, 1000);
}else{
HAL_UART_Transmit(&huart1, (uint8_t[]){0xFF, 0xFF, 0xFF}, 3, 1000);
}
}
if(cmd == 0xBB) {
uint64_t readData[5];
flashReadData(6, readData, 5);
//HAL_UART_Transmit(&huart1, (uint8_t[]){0xBB, 0xBB, 0xBB}, 3, 1000);
HAL_UART_Transmit(&huart1, (uint8_t[]){0xFF, 0xFF, 0xFF}, 5, 1000);
}
if(cmd != 0xAA && cmd != 0xBB) {
HAL_UART_Transmit(&huart1, (uint8_t[]){0xFF, 0xFF, 0xFF}, 3, 1000);
}
}
/* 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 CPU, AHB and APB busses clocks
*/
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 busses 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();
}
}
/* 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 */
/* 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,
tex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
/* USER CODE END 6 */
}
#endif /* USE_FULL_ASSERT */
/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/
此处代码通过串口发送0xAA 0xAA 0xAA,设置0xAA, 0xBB, 0xCC, 0xDD, 0xEE；发送0xBB 0xBB 0xBB 读取存入的内容。
刚开始接触STM32相关硬件，如果有误导的地方，恳请一定指出！ 防止误让其他人走弯路。