# ESP-12E (ESP8266): specs and pinout > A bare Ai-Thinker ESP-12E Wi-Fi module (ESP8266 with 4 MB flash and PCB antenna) with 22 pads at 2 mm pitch. [HTML version](https://soldr.ai/docs/boards/esp-12e) [Docs](https://soldr.ai/docs) / [Boards](https://soldr.ai/docs/boards) A bare Ai-Thinker ESP-12E Wi-Fi module (ESP8266 with 4 MB flash and PCB antenna) with 22 pads at 2 mm pitch. Every value cites its sourceOfficial pinout [Buy on Compoden](https://compoden.com/products/wifi-serial-transceiver-module-esp8266-esp-12e) ## Specs | Spec | Value | Source | |---|---|---| | Operating voltage | 3.0 V to 3.6 V (3.3 V typical) | source Table 1 (p.6); Table 8 Recommended Operating Conditions (p.14) | | Average operating current | 80 mA | source Table 1 Parameters (p.6) | | Operating temperature | -40 C to 125 C | source Table 1 (p.6); Table 8 (p.14) | | Wi-Fi | 802.11 b/g/n, 2.4 GHz (2400-2483.5 MHz); station / softAP / SoftAP+station | source Table 1 Parameters (p.6) | | Flash | 4 MB external SPI flash | source Section 3 (p.9); 4.2.2 (p.11) | | Size | 16 mm x 24 mm x 3 mm, pin pitch 2 mm | source Table 5 Dimension (p.11) | | I/O levels | VIL max 0.25 VDD; VIH min 0.75 VDD, max VDD + 0.3 V; VOL max 0.1 VDD; VOH min 0.8 VDD | source Table 9 Digital Terminal Characteristics (p.14) | | ADC input range | 0 to 1 V | source Table 3 Pin Descriptions, pin 2 (p.7) | | Deep-sleep current | 10 uA typical | source Table 11 Power Consumption (p.16) | ## Power | | Value | Source | |---|---|---| | Supply | 3.0 V to 3.6 V (3.3 V typ) | source Table 11 Power Consumption (p.16) | | Current | TX 802.11b 170 mA (+17 dBm), 11g 140 mA, 11n 120 mA; RX 50 to 56 mA; modem-sleep 15 mA; light-sleep 0.9 mA; deep-sleep 10 uA | source Table 11 Power Consumption (p.16) | ## Pinout Pin names and functions are copied from the Ai-Thinker ESP-12E Specification v1.0 (module, 22 pads). Any adapter board used with it is a separate product. | Pin | Function | Voltage | Notes | Source | |---|---|---|---|---| | 1 | RST | | Reset the module | source Table 3 Pin Descriptions (p.7-8) | | 2 | ADC | | A/D conversion result. Input voltage range 0-1v, scope: 0-1024 | source Table 3 Pin Descriptions (p.7-8) | | 3 | EN | | Chip enable pin. Active high | source Table 3 Pin Descriptions (p.7-8) | | 4 | IO16 | | GPIO16; can be used to wake up the chipset from deep sleep mode | source Table 3 Pin Descriptions (p.7-8) | | 5 | IO14 | | GPIO14; HSPI_CLK | source Table 3 Pin Descriptions (p.7-8) | | 6 | IO12 | | GPIO12; HSPI_MISO | source Table 3 Pin Descriptions (p.7-8) | | 7 | IO13 | | GPIO13; HSPI_MOSI; UART0_CTS | source Table 3 Pin Descriptions (p.7-8) | | 8 | VCC | 3.3 V | 3.3V power supply (VDD) | source Table 3 Pin Descriptions (p.7-8) | | 9 | CS0 | | Chip selection | source Table 3 Pin Descriptions (p.7-8) | | 10 | MISO | | Slave output Main input | source Table 3 Pin Descriptions (p.7-8) | | 11 | IO9 | | GPIO9 | source Table 3 Pin Descriptions (p.7-8) | | 12 | IO10 | | GPIO10 (written GBIO10 in the sheet) | source Table 3 Pin Descriptions (p.7-8) | | 13 | MOSI | | Main output slave input | source Table 3 Pin Descriptions (p.7-8) | | 14 | SCLK | | Clock | source Table 3 Pin Descriptions (p.7-8) | | 15 | GND | | GND | source Table 3 Pin Descriptions (p.7-8) | | 16 | IO15 | | GPIO15; MTDO; HSPICS; UART0_RTS | source Table 3 Pin Descriptions (p.7-8) | | 17 | IO2 | | GPIO2; UART1_TXD | source Table 3 Pin Descriptions (p.7-8) | | 18 | IO0 | | GPIO0 | source Table 3 Pin Descriptions (p.7-8) | | 19 | IO4 | | GPIO4 | source Table 3 Pin Descriptions (p.7-8) | | 20 | IO5 | | GPIO5 | source Table 3 Pin Descriptions (p.7-8) | | 21 | RXD | | UART0_RXD; GPIO3 | source Table 3 Pin Descriptions (p.7-8) | | 22 | TXD | | UART0_TXD; GPIO1 | source Table 3 Pin Descriptions (p.7-8) | ## Build with it Project ideas for the ESP-12E (ESP8266). Each link opens Soldr with the prompt filled in; Soldr assigns the pins, checks power and shows how to wire every part. - [Deep-sleep temperature node](https://app.soldr.ai/?prompt=I%20want%20to%20build%20a%20battery-style%20Wi-Fi%20temperature%20node%20with%20an%20ESP-12E%20module%20and%20a%20DS18B20%20waterproof%20probe): The adapter holds the module and the USB serial board flashes it; the sheet says GPIO16 (pin 4) can wake the chip from deep sleep. A learning project. - [Wi-Fi weather display](https://app.soldr.ai/?prompt=I%20want%20to%20build%20a%20Wi-Fi%20temperature%20and%20humidity%20display%20with%20an%20ESP-12E%20module%2C%20a%20DHT22%20and%20a%200.96%20inch%20OLED): I2C OLED and the DHT22 data pin on free GPIOs; avoid GPIO0, 2 and 15 for them because of their boot roles. - [Wi-Fi DC current and voltage logger](https://app.soldr.ai/?prompt=I%20want%20to%20build%20a%20Wi-Fi%20DC%20current%20and%20voltage%20logger%20with%20an%20ESP-12E%20module%20and%20an%20INA219%20current%20sensor%20module): The INA219 chip runs from 3 to 5.5 V and measures bus voltage from 0 to 26 V over I2C (TI datasheet), so it can use IO4 and IO5 (pins 19 and 20) at 3.3 V logic; the CJMCU module itself is not documented, so check its markings. Learning project: keep the measured circuit low-voltage. ## Common mistakes - Supply is 3.0 to 3.6 V only; 5 V on VCC exceeds the sheet range (source: [link](https://aithinker-static.oss-cn-shenzhen.aliyuncs.com/docs/Public%20Document%20Center/WiFi/esp8266/Specification/ESP-12E%20Specification-20220807.pdf), Table 8, p.14). - Boot mode is set by GPIO15, GPIO0 and GPIO2: UART download needs GPIO15 low, GPIO0 low, GPIO2 high; flash boot needs GPIO15 low, GPIO0 high, GPIO2 high (source: [link](https://aithinker-static.oss-cn-shenzhen.aliyuncs.com/docs/Public%20Document%20Center/WiFi/esp8266/Specification/ESP-12E%20Specification-20220807.pdf), Table 4 Pin Mode, p.8). - The ADC pin accepts 0 to 1 V only (source: [link](https://aithinker-static.oss-cn-shenzhen.aliyuncs.com/docs/Public%20Document%20Center/WiFi/esp8266/Specification/ESP-12E%20Specification-20220807.pdf), Table 3, p.7). ## Not covered by the official source - Sheet has ESP-12E and ESP-12F style headings; the sheet copyright is 2015 and its version is 1.0. ## Sources - [link](https://aithinker-static.oss-cn-shenzhen.aliyuncs.com/docs/Public%20Document%20Center/WiFi/esp8266/Specification/ESP-12E%20Specification-20220807.pdf) (ESP-12E Specification v1.0, Ai-Thinker, file dated 2022-08-07) - [link](https://www.espressif.com/sites/default/files/documentation/0a-esp8266ex_datasheet_en.pdf) (ESP8266EX Datasheet v7.1)