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

Welcome to the Arduino IDE 2.x compatible extensions repository! This repository was created to provide a comprehensive and up-to-date list of extensions that can be used with version 2.x of the ...

[Damian Peckett] has implemented an Apple ] [, its 6502 processor, and a cassette port, all on an Arduino Uno. If that wasn’t enough, he also uses a PS/2 keyboard for input and outputs analog VGA.

Waveshare R7FA4 Plus A Both the Waveshare R7FA4 Plus A and B boards are functionally equivalent to the Arduino UNO R4 Minima and WiFi boards, except for the additional support for 3.3V Arduino shields ...

Arduino also upgraded the R4 WiFi's analog-to-digital converter (ADC), which is responsible for reading data from the analog inputs. On the Rev3, the ADC supports up to 10-bit resolution, with ...

Scheduled to appear in late May, Uno R4 will come in two versions: the plain ‘Uno R4 Minima’, and ‘Uno R4 WiFi’ with an Espressif S3 WiFi module that also gives it Bluetooth Low Energy. “We ...