The Pololu A-Star 32U4 Prime is a general-purpose programmable board based on the ATmega32U4 AVR microcontroller from Microchip (formerly Atmel) and arranged in the common Arduino form factor exemplified by the Uno R3 and Leonardo. As such, the A-Star Prime (abbreviated A* Prime) is compatible with many Arduino shields, including all of the Arduino shields we carry. All 26 of the microcontroller's GPIO lines are accessible on the board, including seven than can be used as PWM outputs and twelve that can be used as analog inputs. The ATmega32U4 is capable of native full-speed USB, which makes it more versatile than similar boards that rely on USB-to-serial adapters: in addition to supporting a virtual (CDC) serial/COM port interface, the A-Star can appear to a connected computer as a mouse and keyboard. The A-Star's USB interface can be accessed through its USB Micro-B connector.
The A* Prime supports the on-board microcontroller with many additional features and improvements over competing products, including enhanced connectivity and superior power management. The Prime is available in two main versions: LV, which features a blue solder mask and a step-up/step-down voltage regulator that allows operation from 2 V to 16 V, and SV, which features a green solder mask and a switching step-down regulator that allows operation from 5 V to 36 V. Each version is available in several different configurations: with or without preinstalled through-hole components like standard Arduino female headers and with or without microSD support. There is also a configuration available for each version with an 8×2 character LCD.
- 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
- Convenient 0.1"-spaced power, ground, and signal connection points
- Buzzer option for simple sounds and music
- microSD support (microSD version only)
- HD44780-based character LCD option
- 3 user-controllable LEDs
- 3 user pushbuttons
- Reset button
- Power features:
- Can be powered from USB or from an external source (with several access points for connecting external power)
- LV operating range: 2 V to 16 V (Note: it requires an input voltage of at least 3 V to start, but it can operate down to 2 V after startup)
- SV operating range: 5 V to 36 V
- Switching 5 V regulator enables efficient operation
- 3.3 V rail supplied by 300 mA linear regulator
- 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
- 6-pin ISP header for use with an external programmer
This configuration of the A-Star 32U4 Prime LV includes microSD support and is assembled with through-hole components as shown in the picture above so that all the basic features can be used without any additional soldering. The standard female headers common to many Arduinos are preinstalled, as is the 2×3 male ISP header, 2×7 male LCD connector, buzzer, DC power jack, and shorting block headers for enabling the microSD hardware, buzzer, and battery voltage monitor. A removable 8×2 character LCD is included with this configuration, and a preinstalled 2-pin terminal block provides an alternate way of supplying input power to the board. This is the LV version of the A-Star Prime, which operates from 2 V to 16 V.
- Size:2.8" × 2.1" (common Arduino form factor)
- Weight:33 g
- Processor:ATmega32U4 @ 16 MHz
- RAM size:2560 bytes
- Program memory size:32 Kbytes1
- Motor channels:0
- User I/O lines:26
- Input voltage range:2 V to 16 V (LV)
- Minimum operating voltage:2 V2
- Maximum operating voltage:16 V
- Maximum output current:1.8 A3
- Logic voltage:5 V
- Reverse voltage protection?:Y
- External programmer required?:N
- Version:includes an 8x2 character LCD, microSD support and preinstalled female headers
- Note that 4 KB of the MCU's 32 KB of flash memory is used by the pre-installed USB bootloader. All 32 KB is available when programming via the ISP header rather than the bootloader.
- Note: the minimum startup voltage is 3 V, but the regulator can operate down to 2 V after startup.
- Available current depends on input voltage, current consumed by the board, ambient conditions, and regulator topology. See product documentation and performance graphs for details.
1x Pololu A-Star 32U4 Prime LV microSD with LCD