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Most common modules ESP-NN seem to come from AI-Thinkers vendor. Espressif Systems themselves have produced the ESP-WROOM-02 Wi-Fi Module.

There are also modules from other vendors, such as :

and other unknown vendors are starting to become available.

Apparently new versions of older modules are appearing with larger flash sizes. To check the flash size of your module:

  • # –port /dev/ttyUSB0 –baud 115200 flash_id
  • Connecting…
  • Manufacturer: c8
  • Device: 4013

Then check out the combo at

  • manufacturer c8 is GigaDevice and device 4013 is GD25Q40, which is a 4Mbit=512KByte device
  • manufacturer ef is Winbond (ex Nexcom) and device 4016 is W25Q32, which is a 32Mbit=4MByte device

ESP-WROOM-02 By Espressif Systems




Note: Some batches of this module ship with LED Current limiting resistors of the wrong value (47Ohm vs 4.7KOhm). This usually results in the power LED vanishing in a puff of smoke.



Pin Name Alternate Functions Notes
1 GND (Pin 1 is in the corner close to the crystal and away from antenna)
2 NC
3 UTXD SPICS1, GPIO1, CLK_RTC Typically used as serial uart0 TX
4 URXD I2SO_DATA, GPIO3, CLK_XTAL Typically used as serial uart0 RX
5 GPIO16 XPD_DCDC, RTC_GPIO0, EXT_WAKEUP, DEEPSLEEP Connected to XPD_DCDC ESP pin, can also be connected to ESP EXT_RSTB (reset) pin by closing jumper near pin 8; Reset pin is active low and has an internal weak pull-up; Connecting jumper is required to wake-up ESP from deep-sleep: RTC produces pulse on XPD_DCDC pin that needs to be fed into EXT_RSTB pin
6 CH_PD Power-down: low input powers down chip, high powers up; tie high for normal operation or module will not function
7 ANT Wifi Antenna, do not connect
8 VCC 3.3V input (pin 8 is between antenna and ESP chip)
12 GPIO15 MTDO, I2SO_BCK, SP_CS At boot: must be low to enter flash or normal boot (high enters special boot modes)
13 GPIO2 I2SO_WS, U1TXD, U0TXD At boot: must be high to enter flash or normal boot (low enters special boot modes); Typically is used as uart1 TX for debug logging
14 GPIO0 SPICS2, CLK_OUT At boot: low causes bootloader to enter flash upload mode; high causes normal boot




:!: not FCC approved (*) :!:


Note: some versions have an error on silkscreen: GPIO4 and GPIO5 are exchanged!

:!: not FCC approved (*) :!:

under the can by Baoshi

pinout of current 16 pin variant

:!: pinout shows early 14 pin variant

Notable difference between 14 and 16 pins variants is that 16 pins has LEDs outside shield. Also, antenna socket is on the bottom left, whereas 14-pin has antenna on the top left.


:!: not FCC approved (*) :!:

Two versions of ESP-08 are on the market: one with 7×2 pins (like the one in the picture) and probably a new one with 8×2+ant pins (pinout is the same like the new 8×2 ESP-07)




This does not appear to be the version 11 board picture . Pins are not at the right end

From here


:!: not FCC approved(*) :!:

(*) not FCC approved, just labelled to look like they do, not a valid FCC ID on the label

FCC of ESP-12


CE of ESP-12

CE NUMBER: BCTC-141212468



:!: This reverse engineered schematic wrong in flash connection. Check table below :!:


ESP Pin Func Alternate Functions Flash pin Err by bimbo385
18 SDIO_DATA_2 [SPIHD] pin 7 [!HOLD] 3(!WP [IO2])
19 SDIO_DATA_3 [SPIWP] pin 3 [!WP] 7(!HOLD [IO3])
20 SDIO_CMD [SDIO_CMD] pin 1 [!CS]
21 SDIO_CLK [SPICLK] pin 6 [CLK]
22 SDIO_DATA_0 [SPIQ/MISO] pin 2 [DO] 5 (DI [IO0])
23 SDIO_DATA_1 [SPID/MOSI] pin 5 [DI] 2 (DO [IO1])

FIXME Please, fix this table if it possible. FIXME




The etching on the shield reads: 'STM8S003 INSIDE' The etching on the shield reads: 'STM8S003 INSIDE'

Backside of the ESP8266-14 module. The ESP8266-14 module has pins and connections on three sides of the board

ESP8266-14 module with metal shield removed. Underneath the shield there is a 20-pin QFPN chip with the marking 'S033', which according to the STM8S003 datasheet is the proper device marking.

WT8266-S1 By Wireless-Tag

CE of WT8266-S1

FCC of WT8266-S1

Modules Family

Modules shown here together with an external aerial, a large, cheap and poor quality development board together with a small, expensive and high quality development board.

Summary Table

Board ID #Pins Pitch Form factor LEDs Antenna Ant.Socket Shielded Dimensions mm Flash Size in Bytes and (bits)
ESP-01 8 0.1“ 2×4 DIL Yes Etched-on PCB No No 14.3 x 24.8 512KB (4Mb) ××
ESP-02 8 0.1” 2×4 notch No? None Yes No 14.2 x 14.2 512KB (4Mb) ×
ESP-03 14 2mm 2×7 notch No Ceramic No No 17.3 x 12.1 512KB (4Mb) ×
ESP-04 14 2mm 2×4 notch No? None No No 14.7 x 12.1 512KB (4Mb) ×
ESP-05 5 0.1“ 1×5 SIL No None Yes No 14.2 x 14.2 512KB (4Mb) ×
ESP-06 12+GND misc 4×3 dice No None No Yes 16.3 x 13.1 512KB (4Mb) ×
ESP-07 16 2mm 2×8 pinhole Yes Ceramic Yes Yes 21.2 x 16.0 1MB (8Mb) ××
ESP-07S 16 2mm 2×8 pinhole No None Yes Yes 17.0 x 16.0 4MB (32Mb)
ESP-08 14 2mm 2×7 notch No None No Yes 17.0 x 16.0 ?? (please fill if you know)
ESP-08 New 16 2mm 2×8 notch No None No Yes 18.0 x 16.0 ?? (please fill if you know)
ESP-09 12+GND misc 4×3 dice No None No No 10.0 x 10.0 ?? (please fill if you know)
ESP-10 5 2mm ?? 1×5 notch No None No No 14.2 x 10.0 512KB (4Mb) *
ESP-11 8 1.27mm 1×8 pinhole No? Ceramic No No 17.3 x 12.1 512KB (4Mb) *
ESP-12 16 2mm 2×8 notch Yes Etched-on PCB No Yes 24.0 x 16.0 4MB (32Mb) ??
ESP-12F 22 2mm 2×8 notch Yes Etched-on PCB No Yes 24.0 x 16.0 4MB (32Mb)
ESP-12E 22 2mm 2×8 notch Yes Etched-on PCB No Yes 24.0 x 16.0 4MB (32Mb)
ESP-12S 16 2mm 2×8 notch Yes Etched-on PCB No Yes 24.0 x 16.0 4MB (32Mb)
ESP-13 18 1.5mm 2×9 ? Etched-on PCB No Yes 20.0 x 19.9 4MB (32Mb)
ESP-14 22 2mm 2×8 + 6 1 Etched-on PCB No Yes 24.3 x 16.2 ?? (please fill if you know)
ESP-201 22+4 0.1” 2×11 + 4 2 Etched-on PCB ××× Yes No 33.5 x 25.5 512KB (4Mb)
WROOM-02 18 1.5mm 2×9 No Etched on PCB No Yes 20.0 x 18.0 ?? (please fill if you know)
WT8266-S1 18 1.5mm 3×6 1 Etched on PCB No Yes 15.0 x 18.6 4MB (32Mb)

× New firmwares can only be flashed on boards with at least 1MB (8Mb) flash. ×× May be different on different editions of the board. ××× Antenna connector is connected by default, to use PCB antenna switch (solder) the 0Ω resistor to the corresponding position.

esp8266-module-family.txt · Last modified: 2017/08/13 18:11 by waspinator