The Arduino UNO R4 Minima and the Arduino UNO R4 WiFi. But apart from the obvious wireless connectivity hinted by the name what other differences do the microcontrollers have.

The Arduino Uno-compatible board has an MCS-51 (often called 8051 instead) instead of the usual ATmega328P/ATmega168. Specifically, [ElectroBoy] uses the AT89S52.

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The basic functions of the Arduino IDE – pinMode, digitalRead, digitalWrite, and analogRead – are available. Most of the WiFi functions work just like the WiFi shield library.