2016年4月7日 (四) 16:59的版本

1 概述

4KB 为一个扇区 (Sector)

1.1 系统参数区 (System param)

始终为 Flash 的最后 16KB

• 8KB 为初始化射频参数 (esp_init_data_default.bin)，4MB Flash 为：0x3FC000 - 0x3FDFFF (The last sector 12 and 13)
• 8KB 为初始化系统参数 (blank.bin)，4MB Flash 为：0x3FE000 - 0x3FFFFF (The last sector 14 and 15)

皆由 SDK 提供

1.2 用户参数区 (User param)

指 Espressif 提供的示例 (IOT_Demo / AT) 中设定的用户参数区

iBaihe 的参数： 0x3C * 4KB = 0x3C000

COS Platform 参数：

(0x3C + 1) * 4KB = 0x3D000 (SAVE_0)
(0x3C + 2) * 4KB = 0x3E000 (SAVE_1)
(0x3C + 3) * 4KB = 0x3F000 (PARAM_FLAG)

2 Layout Without OTA

Address	Size	Name	                        Description
00000h	4k	boot.bin	                Bootloader
 
3C000h	14k	Param Start Sector
3D000h  1x4k    Param Saved 0
3E000h  1x4k    Param Saved 1
3F000h  1x4k    Param Flag

40000h	240k	app.v6.irom0text.bin	        SDK libraries
7C000h	8k	esp_init_data_default.bin	Default configuration
7E000h	8k	blank.bin	                Filled with FFh. May be WiFi configuration

3 Layout With OTA

3.1 512 和 1024KB

3.2 4096KB

4 SPI Flash Format

• http://esp8266-re.foogod.com/wiki/SPI_Flash_Format

5 SPI Flash Mode

• QIO , for flash that support quad r/w operation(e.g. W25Q)

• QOUT, for flash that support quad read operation(e.g. W25Q)

• DIO, for flash that support dual r/w operation(e.g. W25Q &W25X)

• DOUT, for flash that support dual read operation(e.g. W25Q &W25X)

经测试：

• Winbond 25Q32B 可工作于 DIO / DOUT / QIO /QOUT (Noduino Falcon)

• BergMicro 25Q32A 只可工作于 DIO / DOUT (NodeMCU V1.0 可能是 ESP-12E 接线的问题）

• MXIC 25L80 （小 K mini）只可工作于 DOUT

6 Flash Memory Map

Map the flash

/*
 * Memory map first 8Mbit of flash
 * address space is: 0x4020 0000 - 0x402F FFFF
 */
Cache_Read_Enable (0, 0, 0);

Unmap the flash

Cache_Read_Disable();

6.1 Cache_Read_Enable

void Cache_Read_Enable(uint8 odd_even, uint8 mb_count, unt8 no_idea);

Valid values for odd_even:

 0 – clears bits 24 & 25 of control register 0x3FF0000C
 1 – clears bit 24, sets bit 25

other – clears bit 25, sets bit 24

Function of odd_even:

 0 – allows access to even numbered mb
 1 – allow access to odd numbered mb

other – appears to do the same as 1, there must be a difference but I haven’t worked out what it it

Valid values for mb_count:

 0-7 – set bits 16, 17 & 18 of control register 0x3FF0000C

Function of mb_count:

Which odd or even bank to map (according to odd_even option)

 e.g. mb_count = 0, odd_even = 0 -> map first 8Mbit of flash
 e.g. mb_count = 0, odd_even = 1 -> map second 8Mbit of flash
 e.g. mb_count = 1, odd_even = 0 -> map third 8Mbit of flash
 e.g. mb_count = 1, odd_even = 1 -> map fourth 8Mbit of flash

Valid values for no_idea:

 0 – sets bit 3 of 0x3FF00024
 1 – sets bit 26 of 0x3FF0000C and sets bits 3 & 4 of 0x3FF00024

Function of no_idea:

The clue is in the name, I can’t work out what this does from my experiments, but the SDK always sets this to 1.

• Reverse engineered by Richard Burton: http://richard.burtons.org/2015/06/12/esp8266-cache_read_enable/

7 Reference

• https://www.winbond.com/hq/product/code-storage-flash-memory/serial-nor-flash/?__locale=en&density=8Mbit(1MB)#density