ESP8266 Boot

Boot Options

                                  | GPIO 0 | GPIO 2 | GPIO 15 (MTDO)
----------------------------------|--------|--------|---------
Flash Startup (Normal)            |   1    |   1    |   0
UART Download Mode (Programming)  |   0    |   1    |   0
SD-Card Boot                      |   0    |   0    |   1

Only use Flash Boot and Download Mode

                                  | GPIO 0 
----------------------------------|--------
Flash Startup (Normal)            |   1    
UART Download Mode (Programming)  |   0

Header text	Header text	Header text
ESP-12F	pull GPIO15 low GPIO2 high EN high	GPIO0 for mode
ESP-12S	-	GPIO0 for mode

Enter Into Flash Mode

• Most development board has auto enter into flash mode circuits, more commerial products do not really need this.
• Pull GPIO 0 of ESP8266 before power up or reboot to enter into flash mode. -> So simply hold down GPIO 0 and press once reset will enter into flash mode manully.
• Connect 3.3V/GND/TXD=>RXD/RXD->TXD to target, recommand USB-TTL downloader here

• 

  NWI1072 ESP Relay board, enter into flash mode.

• 

  For our ESP8266 Adapter Board

• 

  See a GIF here, if you successfully enter into flash mode.

• 

  debug info shows enter into flash mode

Boot Debug

• Open arduino IDE, and set baud rate to 74880 on serial, can find esp8266 debug info.

ets Jan  8 2013,rst cause:1, boot mode:(3,6)

load 0x4010f000, len 1384, room 16 
tail 8
chksum 0xef
csum 0xef
csum err
ets_main.c 

• reset causes:

   0: 
   1: normal boot
   2: reset pin
   3: software reset
   4: watchdog reset

• boot device:

   0:
   1: ram
   3: flash

Flash Error Log

• flash size is not correctly selected, in this case should be 16Mbit-C1 instead of 32Mbit

mismatch map 5,spi_size_map 4
system_partition_table_regist fail

Incorrect flash mode

ets Jan  8 2013,rst cause:1, boot mode:(3,7)

load 0x4010f000, len 1384, room 16 
tail 8
chksum 0xef
csum 0xef
csum err
ets_main.c

• Fix:esptool.py write_flash 0x0 Yxxxx.bin
• change to below, add dout SPI flash mode

esptool.py write_flash --flash_mode dout 0x0 Yxxxx.bin

Debug

Hardware Check

• Try to swap TXD and RXD in case it is wrong
• Buttons should be hold down or pressed firmly and properly to make the good connection, it is too tiny button
• On module status Blue LED will blink once on reset
• USB-TTL Compatible with 5V TXD RXD signal, for our relay boards, wiring should be 5V, GND, TXD and RXD. Recommanded USB-TTL debugger boards are CP2102, speed up to 15000000 (Some other boards only do 115200)

Software Correct Boot Mode Output

• Correct flash mode output on arduino baudrate 748800:

ets Jan  8 2013,rst cause:2, boot mode:(1,7)

• Correct normal boot mode output

 ets Jan  8 2013,rst cause:2, boot mode:(3,7)