參考部落格：

• http://wiki.jackslab.org/ESP8266_Flash
• https://blog.csdn.net/xh870189248/article/details/81017735
• https://www.jianshu.com/p/0f8e6831cbad
• https://blog.csdn.net/k7arm/article/details/51812021
• http://club.gizwits.com/thread-5092-1-1.html

前言

• ESP8266Flash介面：platform\mcu\esp8266\bsp\include\espressif\spi_flash.h
• sector：扇區

一、ESP8266 Flash讀寫例程

1、寫入資料：

 spi_flash_erase_sector函式只能每次擦除4KByte，寫的時候，只能在已經擦除的區域裡寫。4KByte就是4096Byte對應十六進位制就是0x1000，而每次寫又得以4個位元組那樣對齊地寫。也就是說擦除一次可以寫入1024次。即可以：

• 擦除第0x201扇區
• 寫資料1的起始地址為：0x201000
• 寫資料2的起始地址為：0x201004
• 寫資料3的起始地址為：0x201008
• 依次累加，讀的時候也是如此

uint32 value;
uint8 *addr_case1 =
 
 (uint8 *)&value;
addr_case1[0]=0x11;
addr_case1[1]=0x12;
addr_case1[2]=0x13;
addr_case1[3]=0x14;

spi_flash_erase_sector(0x201);//擦出當前地址的flash
spi_flash_write(0x201000,(uint32 *)addr_case1,sizeof(addr_case1));//寫flash，4個位元組共32位
printf("write:%02x%02x%02x%02x\r\n",addr_case1[0], addr_case1[1], addr_case1[2], addr_case1[
 
3]);

2、讀取資料：

uint32 value;
uint8 *addr_case1 = (uint8 *)&value;

spi_flash_read(0x201000,(uint32 *)addr_case1,sizeof(addr_case1));//讀取flash值
printf("read:%02x%02x%02x%02x\r\n",addr_case1[0], addr_case1[1], addr_case1[2], addr_case1[3]);

3、解析

typedef enum {
    SPI_FLASH_RESULT_OK,        /**< SPI Flash operating OK */
    SPI_FLASH_RESULT_ERR,       /**< SPI Flash operating fail */
    SPI_FLASH_RESULT_TIMEOUT    /**< SPI Flash operating time out */
} SpiFlashOpResult;


/**
  * @brief  Erase the Flash sector.
  *
  * @param  uint16 sec : 扇區數，從扇區0開始計數，每個扇區長度為 4KB。
  *
  * @return SpiFlashOpResult
  */
SpiFlashOpResult spi_flash_erase_sector(uint16 sec);

 從上面對函式spi_flash_erase_sector()的解釋可以看出：擦除的扇區數是以模組整個的Flash總扇區數來計算的。我使用的是ESP8266-12F模組，預設flash為32Mb也就是4MB。那麼flash的總扇區數為：4*1024 = 4096(kB) 4096/4 = 1024(個扇區）

Running Cesanta flasher (speed 115200)...
params:  ?
MEMORY START
ELSE.... 26
P: OHAI
Writing 4096 @ 0x0... 0 (0 %)
1024 (25 %)
2048 (50 %)
3072 (75 %)
4096 (100 %)

Wrote 4096 bytes at 0x00000000 in 0.4 seconds (89.0 kbit/s)...
Writing 339968 @ 0x1000... 0 (0 %)
1024 (0 %)
2048 (0 %)
......
Wrote 339968 bytes at 0x00001000 in 29.5 seconds (92.3 kbit/s)...
Writing 4096 @ 0x3fc000... 0 (0 %)
1024 (25 %)
2048 (50 %)
3072 (75 %)
4096 (100 %)

Wrote 4096 bytes at 0x003fc000 in 0.4 seconds (88.8 kbit/s)...
Writing 4096 @ 0x3fe000... 0 (0 %)
1024 (25 %)
2048 (50 %)
3072 (75 %)
4096 (100 %)

Wrote 4096 bytes at 0x003fe000 in 0.4 seconds (89.3 kbit/s)...
Leaving...
com closed

以上是在下載ESP8266程式時打印出來的資訊，可以看到：

• 第1個扇區已經被寫了：Wrote 4096 bytes at 0x00000000 …
• 第2個扇區到第332個扇區已經被寫了：Wrote 339968 bytes at 0x00001000 …
• 第1020個扇區已經被寫了：Wrote 4096 bytes at 0x003fc000 …
• 第1022個扇區已經被寫了：Wrote 4096 bytes at 0x003fe000 …

AliOS-Things上的使用例程：

/*
 * Copyright (C) 2015-2017 Alibaba Group Holding Limited
 */

#include <aos/aos.h>
#include <hal/soc/soc.h>
#include "stdio.h"
#include "../../../platform/mcu/esp8266/bsp/include/espressif/spi_flash.h"

// 寫flash
void write_config(void) 
{
    uint32 value, value2, value3, value4;
    value = 1994;
    value2 = 1995;
    value3 = 1996;
    value4 = 1997;

    printf("erase:%d\r\n", spi_flash_erase_sector(0x201));
    printf("write:%d\r\n", spi_flash_write(0x201000, (uint32 *)&value, sizeof(value)));
    printf("write:%d\r\n", spi_flash_write(0x201004, (uint32 *)&value2, sizeof(value2)));
    printf("write:%d\r\n", spi_flash_write(0x201008, (uint32 *)&value3, sizeof(value3)));
    printf("write:%d\r\n", spi_flash_write(0x20100C, (uint32 *)&value4, sizeof(value4)));
    printf("sizeof:%d\r\n", sizeof(value));
} 

//讀取flash內容
void read_config(void) {
    uint32 temp, temp2, temp3, temp4;
    
    printf("sizeof:%d\r\n", sizeof(temp));
    printf("read:%d\r\n", spi_flash_read(0x201000, (uint32 *)&temp, sizeof(temp)));
    printf("read:%d\r\n", spi_flash_read(0x201004, (uint32 *)&temp2, sizeof(temp2)));
    printf("read:%d\r\n", spi_flash_read(0x201008, (uint32 *)&temp3, sizeof(temp3)));
    printf("read:%d\r\n", spi_flash_read(0x20100C, (uint32 *)&temp4, sizeof(temp4)));
    printf("temp:%d\r\n", temp);
    printf("temp2:%d\r\n", temp2);
    printf("temp3:%d\r\n", temp3);
    printf("temp4:%d\r\n", temp4);
} 


int application_start(int argc, char *argv[])
{
    printf("liefyuan's esp8266 :%d\r\n", user_rf_cal_sector_set());

    write_config();

    read_config();

    aos_loop_run();

    return 0;
}