ESP8266 Flash

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ESP8266 Flash

目录  [隐藏]  1 概述 1.1 系统参数区 (System param) 1.2 用户参数区 (User param) 2 Layout Without OTA 3 Layout With OTA 3.1 512 和 1024KB 3.2 4096KB 4 SPI Flash Format 5 SPI Flash Mode 6 Flash Memory Map 6.1 Cache_Read_Enable 7 Reference

1 概述

4KB 为一个扇区 (Sector), The last 16 sectors is the paramter area!
1MB flash is start at 0xF0000
4MB flash is start at 0x3F0000

1.1 系统参数区 (System param)

始终为 Flash 的最后 16KB
4KB 为初始化射频参数 (esp_init_data_default.bin); The last sector 12; 4MB Flash 为：0x3FC000 - 0x3FCFFF
8KB 为初始化系统参数 (blank.bin); The last sector 13 and 14, 4KB + 4KB mirror; 4MB Flash 为：0x3FD000 - 0x3FEFFF
4KB is bootloader parameters area; The last sector 15; 4MB flash is at: 0x3FF000
皆由 SDK 提供

For MJYUN:
8KB is MJYUN parameter area; The last sector 4 and 5, 4KB + 4KB mirror; 4MB flash is: 0x3F4000 - 0x3F5FFF

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

?
Unmap the flash

?

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