Arduino Uno

Boots a compiled public-domain AVR sketch: it prints a greeting on the serial monitor and walks a lit LED across PORTB (D8-D13). The two on-screen buttons are wired to input pins PD2/PD3 and light the top LEDs while held; typing sends bytes to the serial port (USART RX). Open the debugger to single-step the ATmega328P, read/write R0-R31/SP/PC/SREG, watch the I/O registers, set breakpoints and write-watchpoints. Click the panel first so it captures the keyboard.

Boots a compiled public-domain AVR sketch: it prints a greeting on the serial monitor and walks a lit LED across PORTB (D8-D13). The two on-screen buttons are wired to input pins PD2/PD3 and light the top LEDs while held; typing sends bytes to the serial port (USART RX). Open the debugger to single-step the ATmega328P, read/write R0-R31/SP/PC/SREG, watch the I/O registers, set breakpoints and write-watchpoints. Click the panel first so it captures the keyboard.