esp8266_memory_map
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Table of Contents
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ESP8266 Memory Map
This page describes the physical memory layout of the ESP8266 family.
Reset Vector
The reset vector is 40000080h, which maps to internal ROM.
Memory Layout
| Address | Name | Size | Type | R/W | Description |
| ———: | —— | ———-: | :—-: | — | ———– |
| 00000000h | Exc | ||||
| 20000000h | No | ||||
| 3FF00000h | dport0 | 1000h | I/O | RW? | |
| 3FF10000h | No | ||||
| 3FF20000h | ? | ? | RW? | ||
| 3FF30000h | No | ||||
| 3FFC0000h | ? | 20000h | ? | RW? | |
| 3FFE0000h | No | ||||
| 3FFE8000h | dram0 | 14000h | RAM | RW | |
| 3FFFC000h | 4000h | RAM | |||
| 40000000h | brom? | 10000h | ROM | RW? | |
| 40010000h | No | ||||
| 40100000h | iram1 | 8000h | RAM | RW | |
| 40108000h | ? | ||||
| 40140000h | ? | ||||
| 40200000h | ? | ||||
| 40300000h | ? | ||||
| 60000000h | ? | 1000h | I/O | RW? | |
| 60001000h | ? | 800h | ? | RW? | |
| 60001800h | ? | 800h | ? | RW? | |
| 60002000h | Exc | ||||
| 70000000h | 90000000h | No |
SPI Flash ROM Layout (without OTA upgrades)
This is for ESP IoT SDK version 0.8 and above.
| Address | Size | Name | Description |
| ——- | —- | ————————- | ——————— |
| 00000h | 248k | app.v6.flash.bin | |
| 3E000h | 8k | masterdevicekey.bin | |
| 40000h | 240k | app.v6.irom0text.bin | |
| 7C000h | 8k | espinitdata_default.bin | |
| 7E000h | 8k | blank.bin |
SPI Flash ROM Layout (with OTA upgrades)
This is for ESP IoT SDK version 0.8 and above, supporting OTA upgrades.
| Address | Size | Name | Description |
| ——- | —- | ——————— | ———————— |
| 00000h | 4k | boot.bin | Bootloader |
| 01000h | 64k | app.v6.flash1.bin | User application, slot 1 |
| 11000h | 180k | app.v6.irom0text1.bin | SDK libraries, slot 1 |
| 3E000h | 8k | masterdevicekey.bin | OTA device key |
| 40000h | 4k | Unused | |
| 41000h | 64k | app.v6.flash1.bin | User application, slot 2 |
| 51000h | 180k | app.v6.irom0text1.bin | SDK libraries, slot 2 |
| 7E000h | 8k | blank.bin | Filled with FFh. May be WiFi configuration. |
Exception Vectors
| Address | Name |
| ——— | ————— |
| 40000010h | DebugException |
| 40000020h | NMIException |
| 40000030h | KernelException |
| 40000050h | UserException |
| 40000070h | DoubleException |
| 40000080h | Reset |
Memmory-Mapped I/O Registers
Most of them live in 60000000h.
| Base Address | Size | Name |
| ————: | —-: | —– |
| 60000000h | 80h | uart0 |
| 60000100h | 100h | spi1 |
| 60000200h | 100h | spi0 |
| 60000300h | 74h | gpio |
| 60000600h | 28h | timer |
| 60000700h | A4h | rtc |
| 60000800h | 44h | iomux |
| 60000F00h | 80h | uart1 |
dport0 (3FF00000h–)
- 3FF00014h is a clock setting register. Setting bit 0 changes the CPU to 160 MHz mode. Clearing it means 80 MHz. Note that you need to call
os_update_cpu_frequency(int freq_in_mhz)when changing the bit. Probably to calibrate timers. The UART divisor is not updated automatically, so you also have to calluart_div_modify(uart_no, clock_freq_in_hz / baud_rate_in_baud).
iomux Pin Registers (60000804h–60000843h)
31 24 16 8 0
-------- -ffff--- -------- ud--UDEe
`- Function || |||`- Output Enable
|| ||`- Output Enable during sleep
|| |`- Pull-down during sleep
|| `- Pull-up during sleep
|`- Pull-down
`- Pull-up
References
- Forum post Memory Layout, p274 - Forum post Firmware Dump, p263 - Forum post Memory Layout, p889 - Forum post Cloud update documentation, p2486 - lx106-rc-2010.1/xtensa-elf/lib/xt2000-rt/memmap.xmm - espiotsdkv0.9.3/examples/IoTDemo/ssl/app/espconn_ssl.c - ESP SDK linker scripts
esp8266_memory_map.1419992966.txt.gz · Last modified: 2014/12/31 02:29 by admin