If we set GPIO0 low, however, the boot ROM inside the ESP8266 takes over and it begins communicating over the UART. Using this boot ROM we can push our programs to the flash memory.

A lot of people have used ESP8266 to add inexpensive WiFi connectivity to their projects, but [Oscar] decided to take it one step further and program an Arduino over WiFi with the ESP8266. [Oscar] … ...

Prestissimo Uno+ Arduino dev board with extra I2C UART SPI ADC IO and PWM channels. 2:24 pm November 5, 2018 By Julian Horsey.