ESP8266 is not just a UART to Wifi Adapter. It is a SOC comprising of full TCP/IP Stack and host of GPIO pins. You can possibly use it in two ways:
- As a serial to wifi Adapter: In this mode the module can be connected to UART pins of the micrcontroller and can be used as any other wifi sheild. It works with Arduino and all other major micrcontrollers out there. Infact this is the way it was marketed.
- As a MCU and Wifi Sheild with Arduino: However, the community found out the way to access the GPIO pins of the SOC and use it bot as a MCU and a WiFi solution. Interestingly, the community added support for the module to work directly with the Arduino IDE. This way one can program the module itself with arduino style code. To do this, you will require a USB to Serial Convertor like the CP2102.
Note that not all versions of ESP8266 Breakout bring all GPIO pins. This breakout is ESP-12E and it brings out 6 more GPIO/SPI Pins. This module is drop in replaceable, pin compatible with EPS12.
- 802.11 b/g/n protocol
- Wi-Fi Direct (P2P), soft-AP
- Integrated TCP/IP protocol stack
- Integrated TR switch, balun, LNA, power amplifier and matching network
- Integrated PLL, regulators, and power management units
- +19.5dBm output power in 802.11b mode
- Integrated temperature sensor
- Supports antenna diversity
- Power down leakage current of < 10uA
- Integrated low power 32-bit CPU could be used as application processor
- SDIO 2.0, SPI, UART
- STBC, 1Ã—1 MIMO, 2Ã—1 MIMO
- A-MPDU & A-MSDU aggregation & 0.4ïs guard interval
- Wake up and transmit packets in < 2ms
- Standby power consumption of < 1.0mW (DTIM3)