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

Arduino Uno gets bendable "Flexduino" remake, flaunting a cheery yellow hue Say goodbye to boards that break when you flex them By Zo Ahmed August 27, 2024, 11:05 ...

Arduino UNO R4 WiFi. Arduino UNO R4 specifications: Microcontroller – Renesas RA4M1 Arm Cortex-M4F MCU @ 48 MHz with 32KB SRAM, 256KB flash; Wireless (Arduino UNO R4 WiFi only) – ESP32-S3-MINI-1 ...

This leap forward starts with a new processor by Renesas, a global leader in microcontrollers, analog, power and SoC products. While over 10 million users have enjoyed playing and working with Arduino ...