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1. Overview

1.1. Supported operating systems

A-Star 32U4 Robot Controller LV with Raspberry Pi Bridge (SMT components only).

A-Star 32U4 Robot Controller SV with Raspberry Pi Bridge (SMT components only).

The Pololu A-Star 32U4 Robot Controller with Raspberry Pi Bridge is a programmable module designed to be the core of a small robot, either as an auxiliary controller atop a Raspberry Pi base or as a complete control solution on its own.

At its heart is an Atmel ATmega32U4 AVR microcontroller, which has 32 KB of flash program memory, 2.5 KB of RAM, and built-in USB functionality. The controller adds a complement of peripheral hardware useful for robotics applications, including dual H-bridge motor drivers capable of delivering at least 1.7 A per channel continuously, as well as an efficient switching voltage regulator and level shifters that enable it to power and communicate with a Raspberry Pi.

This A-Star is available in two versions with different operating voltage ranges: the Robot Controller LV (blue solder mask) accepts a 2.7 V to 11 V input voltage, and the Robot Controller SV (green solder mask) accepts a 5.5 V to 36 V input voltage.

Like other A-Star programmable controllers (abbreviated A*), the robot controller features a USB interface and ships with a preloaded Arduino-compatible bootloader. We provide a software add-on that enables it to be easily programmed from the Arduino environment, as well as an Arduino library to help interface with its on-board hardware.

A USB A to Micro-B cable (not included) is required to connect the A-Star 32U4 Robot Controller to a computer.

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 motor drivers (≥1.7 A 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 external supply through on-board regulator (with several access points for connecting external power)
      • LV: 2.7 V to 11 V input
      • SV: 5.5 V to 36 V input
    • 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

A-Star comparison table







A-Star 328PB Micro A-Star 32U4 Micro A-Star 32U4 Mini ULV

A-Star 32U4 Mini LV

A-Star 32U4 Mini SV
A-Star 32U4 Prime LV

A-Star 32U4 Prime SV
A-Star 32U4 Robot Controller LV

A-Star 32U4 Robot Controller SV
Microcontroller: ATmega328PB ATmega32U4
User I/O lines: 24 18 26 26(1) 26(1)
PWM outputs: 9 7 7 7 7(1)
Analog inputs: 8 8 12 12 12(1)
Ground access points: 6 2 4 43 44
User LEDs: 1 2 3 3 3
User pushbuttons: 3 3
USB interface: yes yes yes yes
Reset button: yes   yes yes yes
Power switch:     yes yes
Buzzer option:     yes yes
microSD option:     yes  
LCD option:     yes  
Motor drivers:       yes
Operating voltage: 3.3V VCC: 3.8 V to 15 V
5V VCC: 5.5 V to 15 V
5.5 V to 15 V ULV: 0.5 V to 5.5 V
LV: 2.7 V to 11.8 V
SV: 5 V to 40 V
LV: 2 V to 16 V
SV: 5 V to 36 V
LV: 2.7 V to 11 V
SV: 5.5 V to 36 V
Regulator type: 3.3 V or 5 V linear 5 V linear 5 V switching

ULV: step-up
LV: step-up/step-down
SV: step-down
5 V switching

LV: step-up/step-down
SV: step-down
5 V switching

LV: step-up/step-down
SV: step-down
Regulated current:(2) 100 mA 100 mA ULV: 500 mA
LV: 1 A
SV: 800 mA
LV: 1.8 A
SV: 1 A
LV: 1 A
SV: 1.5 A
Dimensions: 1.3″ × 0.7″ 1″ × 0.6″ 1.9″ × 0.7″ 2.8″ × 2.1″ 2.6″ × 2.2″
Weight: 1.5 g(3) 1.3 g(3) 3.4 g(3) 13 g to 33 g 14 g to 23 g
Price: $4.95 $12.75 $14.95 to $19.95 $19.95 to $34.95 $24.95 to $39.95
1 Some microcontroller resources are used by on-board hardware.
2 These values are rough approximations for comparison purposes. Available current depends on input voltage, current consumed by the board, ambient conditions, and regulator topology. See product documentation and performance graphs for details.
3 Without included optional headers.

Related Products

A-Star 32U4 Robot Controller LV with Raspberry Pi Bridge (SMT Components Only)
A-Star 32U4 Robot Controller LV with Raspberry Pi Bridge
A-Star 32U4 Robot Controller SV with Raspberry Pi Bridge (SMT Components Only)
A-Star 32U4 Robot Controller SV with Raspberry Pi Bridge
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