Another interesting microcontroller that is quite popular in the Internet of Things (IoT) sector is the ESP8266 chip. It is actually a Wi-Fi chip with microcontroller capabilities. It consists of an L-106 32-bit RISC-based (short for Reduced Instruction Set Computing) Tensilica microcontroller that runs at 80 MHz or overclocked to 160 MHz, with digital peripheral interfaces, antennas, and power modules embedded on a single chip.

Some of its features are that it has 2.4 GHz Wi-Fi (802.11 b/g/n, supporting WPA/WPA2), 16 GPIOs, a 10-bit ADC, and communication interfaces such as I2C, SPI, I2S, UART, and PWM. I2S and UART are available as shared pins, along with GPIOs. Memory size is a 64 KiB boot ROM, 32 KiB instruction RAM, and 80 KiB user data RAM. It also has 32 KiB instruction cache RAM and 16 KiB ETS system data RAM. External flash memory can be accessed using the SPI interface.

The ESP8266 comes in various form factors with different SDKs (short for Software Development Kits). For instance, there is a Lua scripting language-based firmware called NodeMCU that runs on ESP8266 SoC. 

Now, let's look at a few ROS-supported embedded boards.