A-Star 32U4 Prime SV microSD

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Pololu item #: 3114
Brand: Pololu
Status: Active and Preferred 
RoHS 3 compliant


The A-Star 32U4 Prime SV is a programmable board based on the ATmega32U4 AVR microcontroller and arranged in the common Arduino form factor. The A-Star Prime offers many additional features and improvements over competing products, including superior power management that enables efficient operation from 5 V to 36 V. This configuration of the A-Star 32U4 Prime SV includes microSD support and preinstalled female headers common to many Arduinos.

Alternatives available with variations in these parameter(s): version Select variant…

Pictures

A-Star 32U4 Prime SV microSD.

A-Star 32U4 Prime SV microSD.

A-Star 32U4 Prime SV, bottom view.

A-Star 32U4 Prime pinout diagram.

A-Star 32U4 Prime power distribution diagram.

From top to bottom: A-Star 32U4 Micro, Mini SV, and Prime SV.

Typical efficiency of the 5 V regulator on the A-Star 32U4 Prime SV.

Typical maximum output current of the 5 V regulators on the A-Star 32U4 Primes.

Typical dropout voltage of the 5 V regulator on the A-Star 32U4 Prime SV.

Side-by-side comparison of the A-Star 32U4 Prime LV microSD to the Arduino Leonardo.




Overview

A-Star 32U4 Prime SV, bottom view.

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: SV, which features a green solder mask and a switching step-down regulator that allows operation from 5 V to 36 V, and LV, which features a blue solder mask and a step-up/step-down voltage regulator that allows operation from 2 V to 16 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.

A-Star 32U4 Prime SV microSD with LCD.

A-Star 32U4 Prime SV (5 V to 36 V) configurations:

A-Star 32U4 Prime LV microSD with LCD.

A-Star 32U4 Prime LV (2 V to 16 V) configurations:

We carry an A-Star Prime accessory pack that contains an assortment of parts you might want when assembling the configurations without preinstalled headers (items #4005, #4006, #3111, and #3112).

Our comprehensive user’s guide provides the basics you need to get started with the A-Star as well as detailed technical information for advanced users.

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

A-Star 32U4 Prime pinout diagram.

A-Star 32U4 Prime power distribution diagram.

Features

Details for item #3114

A-Star 32U4 Prime SV microSD.

This configuration of the A-Star 32U4 Prime SV 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, buzzer, DC power jack, and shorting block headers for enabling the microSD hardware, buzzer, and battery voltage monitor. This is the SV version of the A-Star Prime, which operates from 5 V to 36 V.

A-Star 32U4 Prime SV 5 V regulator

A major feature of the A* Prime SV is its power system, which allows it to efficiently operate from a 5 V to 36 V external source. The input voltage is regulated to 5 V by an ISL85410 switching step-down (buck) converter from Intersil, a higher-power version of the ISL85418 used on the smaller A-Star 32U4 Mini SV. (We also make a standalone regulator based on this integrated circuit.)

As shown in the left graph below, the SV’s 5 V switching regulator has an efficiency – defined as (Power out)/(Power in) – of 80% to 95% for most combinations of input voltage and load.

The A-Star’s components, including the microcontroller and LEDs, draw 30 mA to 40 mA in typical applications (without the buzzer, microSD card, or an LCD). The rest of the regulator’s achievable output current, which depends on input voltage as well as ambient conditions, can be used to power other devices. The green line in the right graph above shows the output currents where the regulator’s output voltage drops below 4.75 V. These currents are close to the limits of the regulator’s capability and generally cannot be sustained for long periods; under typical operating conditions, a safe limit for the maximum continuous regulator output current is approximately 1 A.

The dropout voltage of a step-down regulator is defined as the minimum amount by which the input voltage must exceed the regulator’s target output voltage in order to assure the target output can be achieved. As can be seen in the graph below, the dropout voltage of the Prime SV’s regulator increases approximately linearly with the output current. For light loads where the dropout voltage is small, the board can operate down to 5 V. However, for larger loads, the dropout voltage should be taken into consideration when selecting a power supply; operating above 6 V will ensure the full output current is available.

Note: Batteries can have much higher voltages than their nominal voltages when fully charged, so be careful with nominal voltages above 24 V. A 36 V battery is not appropriate for this product.

Arduino compatibility

The A-Star 32U4 Prime ships with a preloaded Arduino-compatible bootloader (which uses 4 KB of flash memory, leaving 28 KB available for the user program). We provide a software add-on that enables the board to be easily programmed from the Arduino environment and an Arduino library to make it easy to use the additional on-board hardware. The A-Star 32U4 has the same microcontroller and form factor as the Arduino Leonardo, and it runs at the same frequency, so we generally expect it to work with shields that are compatible with the Leonardo and similar boards. Note that the Prime has additional components and connection points, so you should make sure these do not physically interfere with any shield you are considering using. The following table shows how the Prime compares to the Leonardo and Uno:


Arduino Uno R3

Arduino Leonardo

A-Star 32U4 Prime LV

A-Star 32U4 Prime SV
Microcontroller: ATmega328P ATmega32U4 ATmega32U4
Clock: 16 MHz resonator 16 MHz crystal 16 MHz crystal
User I/O lines: 20 23 26
PWM outputs: 6 7 7
Analog inputs: 6 12 12
Ground access points: 4 4 43
User LEDs: 3 3 3
User pushbuttons: 3
Reset button: yes yes yes
Power switch:     yes
Buzzer option:     yes
microSD option:     yes
LCD option:     yes
Arduino-compatible
bootloader:
yes yes yes
USB connector: B Micro-B Micro-B
USB/regulator
power selection:
partial partial TPS2113A
High-performance
reverse-voltage
protection:
    yes
Recommended
input voltage:
7 V to 12 V 7 V to 12 V 2 V to 16 V 5 V to 36 V
Regulator type (5 V): linear linear switching
step-up/step-down
switching
step-down
Available
5 V
output
current:
at 3 V in 0.75 A
at 5 V in 1.5 A 0.2 A
at 7 V in 1.0 A 1.0 A 1.9 A(1) 1.0 A
at 9 V in 0.5 A 0.5 A 1.9 A(1) 1.0 A
at 11 V in 0.35 A 0.35 A 1.8 A 1.0 A
at 24 V in 1.0 A
via USB
connector
0.5 A(2) 0.5 A(2) 1.9 A(3) 1.9 A(3)
Weight: 28 g 20 g 13 g to 33 g
Price: $27.60 $24.95 $24.95 to $39.95
1 There is more available 5 V output current via VREG, see maximum regulator output current graph for details.
2 With sufficient USB power supply.
3 Nominal current available through power MUX with sufficient USB power supply.

Side-by-side comparison of the A-Star 32U4 Prime LV microSD to the Arduino Leonardo.

The A-Star family

From top to bottom: A-Star 328PB Micro, 32U4 Micro, 32U4 Mini SV, and 32U4 Prime SV.

The A-Star 32U4 Micro is a part of our larger A-Star family, all of whose members are based on AVR microcontrollers and are preloaded with Arduino-compatible bootloaders. The table below shows some key features and specifications of our A-Star microcontroller boards to help you choose the right one for your application.







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)
Available PWM outputs: 9 6 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: $8.95 $16.95 $24.95 to $24.95 $24.95 to $39.95 $29.95 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.

Dimensions

Size: 2.8″ × 2.1″ (common Arduino form factor)
Weight: 20 g

General specifications

Processor: ATmega32U4 @ 16 MHz
RAM size: 2560 bytes
Program memory size: 32 Kbytes1
Motor channels: 0
User I/O lines: 26
Input voltage range: 5 V to 36 V (SV)
Minimum operating voltage: 5 V2
Maximum operating voltage: 36 V
Maximum output current: 1.0 A3
Logic voltage: 5 V
Reverse voltage protection?: Y
External programmer required?: N
Version: includes microSD support and preinstalled female headers

Identifying markings

PCB dev codes: ac03c
Other PCB markings: 0J8661

Notes:

1
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.
2
For light loads. The regulator's dropout voltage increases approximately linearly with the load, from a few millivolts at no load up to around 0.9 V at 1 A.
3
Available current depends on input voltage, current consumed by the board, ambient conditions, and regulator topology. See product documentation and performance graphs for details.

Documentation and other information

File downloads

Recommended links

Frequently-asked questions

No FAQs available.

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