This A-Star is based on the ATmega32U4 AVR microcontroller from Microchip (formerly Atmel), which has built-in USB functionality, and it ships with a preloaded Arduino-compatible bootloader. Its complement of peripheral hardware includes dual motor drivers capable of delivering a continuous 1.7 A per channel, along with pushbuttons, LEDs, and an optional buzzer for building a user interface. An efficient switching voltage regulator allows the controller to work over a wide range of input voltages (5.5 V to 36 V). The robot controller board conforms to the Raspberry Pi HAT specification, allowing it to be used as an add-on for a Raspberry Pi with a 40-pin GPIO header (Model B+ or newer, including Pi 3 Model B+ and Model A+). On-board level shifters make it easy to set up I²C communication and interface other signals between the two controllers, and the A-Star automatically supplies 5 V power to an attached Raspberry Pi. In this setup, the Raspberry Pi can handle the high-level robot control while relying on the A-Star for low-level tasks like reading analog sensors and controlling timing-sensitive devices.

Versions:

Surface mount components only: This version of the A-Star 32U4 Robot Controller SV with Raspberry Pi Bridge (5.5 V to 36 V input voltage) does not include any through-hole components.
Assembled with selected through-hole components: This version of the A-Star 32U4 Robot Controller SV with Raspberry Pi Bridge (5.5 V to 36 V input voltage) is assembled with selected through-hole connectors and components for use as a Raspberry Pi expansion board

Features:

Dimensions: 65 mm × 56 mm (2.6″ × 2.2″)
Programmable ATmega32U4 MCU with 32 KB flash, 2.5 KB SRAM, 1 KB EEPROM, and native full-speed USB (clocked by precision 16 MHz crystal oscillator)
Preloaded with Arduino-compatible bootloader (no external programmer required)
All 26 general-purpose I/O lines from the ATmega32U4 are broken out (including PB0, PD5, and PE2); 7 of these can be used as hardware PWM outputs and 12 of these can be used as analog inputs (some I/O lines are used by on-board hardware)
Convenient 0.1″-spaced power, ground, and signal connection points
Dual bidirectional MAX14870 motor drivers (1.7 A continuous per channel, 2.5 A peak per channel)
Buzzer option for simple sounds and music
3 user-controllable LEDs
3 user pushbuttons
Reset button
Level shifters for interfacing 5 V logic to 3.3 V Raspberry Pi
Power features:
- 5 V power can be sourced from USB or from 5.5 V to 36 V external supply through on-board regulator (with several access points for connecting external power)
- Switching 5 V regulator enables efficient operation
- Power switch for external power inputs
- Reverse-voltage protection on external power inputs
- Power selection circuit allows for seamless switching between power sources while providing overcurrent protection, and feedback about which power source is selected
- Provides 5 V power to Raspberry Pi
6-pin ISP header for use with an external programmer
Comprehensive user’s guide

Specifications:

Processor: ATmega32U4 @ 16 MHz
RAM size: 2560 bytes
Program memory size: 32 Kbytes
Motor driver: MAX14870
Motor channels: 2
User I/O lines: 26
Input voltage range: 5.5 V to 36 V
Minimum operating voltage: 5.5 V
Maximum operating voltage: 36 V
Maximum output current: 2.5 A
Continuous output current per channel: 1.7 A
Peak output current per channel: 2.5 A
Logic voltage: 5 V
Reverse voltage protection?: Y
External programmer required?: N

Note: This product requires a USB A to Micro-B cable (not included) to connect to a computer

Package Includes:

1 x Pololu 3118 / 3119 A-Star 32U4 Robot Controller SV with Raspberry Pi Bridge

Processor Specifications
Speed	16 MHz
Controller Specifications
Family Name	ATmega32U4
Memory Specifications
RAM	2560 bytes
Electrical Specifications
Output Current	2.5 A
Minimum Operating Voltage	5.5 V
Maximum Operating Voltage	36V
Additional Information
Warranty