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Arduino Mega vs Uno — Reviews and Buyer’s Guide

arduino mega vs uno You are in your first semester of engineering school. Your instructor introduces the subject of electronics to the class. She does a good job explain the topic, but you want to get some hands-on training to re-enforce the discussion. Where do you start?

This article will compare two of the most popular micro-controller boards in the world: Arduino Mega and Uno. Base on the analysis, I will recommend which board best suits the needs of a beginner.

What is a Starter Kit?

A micro-controller starter kit is a tool used to train new students, hobbyists and anyone else who wants to know about how controllers work.

A micro-controller is a computer chip used to direct the actions of products like wearable technology, drones, microwaves and remote controls. The unit can be slow, highly integrated, easy to program, require no operating system.

What is an Arduino?

An Arduino is micro-controller board that lets you read information from the world around you and send commands to the exterior world.

The board is part of the world’s leading open-system hardware and software ecosystem. The company offers a wide range of software tools, hardware platforms and documentation to allow you to use technology in creative ways.

Arduino is a popular tool for Internet of Things (IoT) projects. It also serves an important role in STEM/STEAM education. We compared Arduino Mega vs Uno.

Arduino Mega vs Uno 2020

ModelIncludes 
Arduino Uno14 digital input/output pins, 6 analog inputs
Arduino Mega54 digital I/O pins, 16 analog inputs
Arduino Leonardo20 digital I/O Pins, 12 analog pins
We aim to show you accurate product information. Manufacturers, suppliers, and others provide what you see here, and we have not verified it. See our disclaimer.

Arduino Uno R3

Arduino Uno R3The Arduino Uno is a micro-controller board based on the ATmega328P chip. It has 14 digital input/output pins. Six of the pins can be used as PWM outputs.

The board also has six analog inputs, a 16 MHz quartz crystal, USB connection, power jack, ISCP header and a reset button.

It contains everything needed to support the micro-controller. Just connect the board to a computer with an USB cable to power it up.

You can also power the board using a AC-to-DC adapter or connect it to a battery source. If for some reason you do something wrong, the computer chip is easily replaced.

Technology:

As mentioned above, the Uno uses the ATmega328P computer chip. It is a high performance, low-power AVR 8-bit micro-controller.

The AVR core combines its 32 general purpose registers with a plush instruction set. Because all the registers are connected to the arithmetic logic unit (ALC), two independent registers can be accessed during a single clock cycle.

The ATmega328P has the following features:

  • 32K Bytes of in-system programmable flash with read-while-write capabilities
  • 1K byte EEPROM
  • 2K bytes SRAM
  • 23 general purpose I/O lines
  • Three flexible time/counters with compare modes
  • Internal and external interrupts
  • Serial programmable USART
  • an SPI serial port
  • 6-channel 10-bit ADC
  • Five software selectable power saving mode

Programming:

The board can be program using the Arduino software IDE. The ATmega328P comes programmed with a bootloader. This feature allows you to upload new code to the controller without the use of an external hardware programmer.

New firmware can be uploaded using either the ATMEL’s FLIP software (Windows) or DFU Programmer (Mac OS X or Linux).

Communication

Arduino Uno communicates with other devices (a computer, another Arduino board, or other micro-controllers) through numerous communication facilities. Available on digital pins 0 (RX) and 1 (TX), the ATmega328 provides UART TTL (5V) serial communication.

The serial communications is channeled over via USB. Then, an ATmega16U2 on the board appears as a virtual com port to software on the computer. The firmware uses the standard USB COM drivers.

No external driver is needed. However, you must use an .inf file on a Windows system. a serial monitor is included with the Arduino Software (IDE). It allows simple textual data to be sent to and from the board.

The RX and TX LEDs on the board will flash when data is being transmitted via the USB-to-serial chip and USB connection to the computer (but not for serial communication on pins 0 and 1).

Automatic (Software) Reset

You do not have to press the physical reset button before any uploads. The Arduino Uno board is designed to allow a reset to be sent via software running on a connected computer.

A hardware flow control line (DTR) of the ATmega8U2/16U2 is connected to the reset line of the ATmega328 (via a 100 nanofarad capacitor). When this line is taken low, the reset line drops long enough to reset the chip.

You can press the upload button on the interface toolbar to activate this feature in the Arduino Software (IDE). Then, the bootloader will have a shorter timeout. This action allows the coordination of lowering the DTR the start of the upload.

Why you should choose an Arduino Uno?

The Arduino Uno is the most standard board available on the market. Because of this, the board is an excellent choice for beginners. This all-purpose board purpose board provides features for beginners to learn about the Arduino platform and electronics.

Recommendation

I recommend the Uno for students, novice engineers and anyone who have an interest in building an electronics project. The micro-controller board is supported through an outstanding open-source system. If you encounter any problems, you could refer to the Arduino ecosystem for advice and suggestions.
Pros
  • Easy to use
  • Can quickly prototype projects
  • Can quickly deploy board in testing environments
  • Open-source nature allows you to create a custom board
Cons
  • Limited processing power
  • Power consumption is higher than latest ARM based boards
  • Limited input/output pins


Arduino Mega 2560

Arduino Mega 2560The Arduino Mega is a micro-controller board that utilizes the ATmega2560 computer chip.

It has 54 digital input/output pins. 15 of these pins can be used as PWM outputs.

The board also includes 16 analog inputs, four UARTS hardware serial ports, 16 MHz crystal oscillator, a USB connection, a power jack, a ICSP header and a reset button.

Technology:

As mentioned above, the Mega uses the ATmega2560 computer chip. It is a high performance, low-power AVR RISC-based 8-bit micro-controller.

The AVR core combines its 32 general purpose registers with a plush instruction set. Because all the registers are connected to the arithmetic logic unit (ALC), two independent registers can be accessed during a single clock cycle.

The ATmega2560 has the following features:

  • Two 8-bit Timer/Counters with Separate Prescaler and Compare Mode
  • Four 16-bit Timer/Counter with Separate Prescaler, Compare- and Capture Mode
  • Real Time Counter with Separate Oscillator
  • Four 8-bit PWM Channels
  • Twelve PWM Channels with Programmable Resolution from 2 to 16 Bits
  • Output Compare Modulator – 16-channel, 10-bit ADC
  • Four Programmable Serial USART
  • Master/Slave SPI Serial Interface
  • Byte Oriented 2-wire Serial Interface
  • Programmable Watchdog Timer with Separate On-chip Oscillator
  • On-chip Analog Comparator
  • Interrupt and Wake-up on Pin Change

Programming

The board can be program using the Arduino software IDE. The ATmega328P comes programmed with a bootloader. This feature allows you to upload new code to the controller without the use of an external hardware programmer.

New firmware can be uploaded using either the ATMEL’s FLIP software (Windows) or DFU Programmer (Mac OS X or Linux).

Automatic (Software) Reset

With the Mega, you are not required to physically press the reset button prior to an upload. The Mega board’s design allows you to reset the micro-controller via software running on a connected computer.

A hardware flow control line (DTR) of the ATmega8U2 is directly connected to the reset line of the ATmega2560 (via a 100 nanofarad capacitor). When this line is taken low, the reset line drops long enough to reset the chip.

The Arduino Software (IDE) also uses the capability to upload code by simply pressing the upload button in the Arduino environment. As a result, the bootloader can have a shorter timeout. Thus, the DTR lowering can be coordinated with the start of the upload.

There are other implications of this setup. When the Mega board is connected to either a computer running Mac OS X or Linux, it resets each time a connection is made to it from software (via USB).

For the next half-second or so, the bootloader is running on the ATMega2560. Even though the board is programmed to ignore malformed data (i.e. anything besides an upload of new code), it will intercept the first few bytes of data sent to the board after a connection is opened.

If a sketch running receives one-time configuration or any other data during start-up, ensure that the software that is communicating with the board delays a second after opening the connection and before sending its data.

You can disable the auto-reset by cutting the trace on the Mega 2560 board. To re-enable the reset, you can solder pads on either side of the trace. It is labeled “RESET-EN”. The auto-reset can also be disabled by connecting a 110 ohm resistor from 5V to the reset line.

Arduino Mega vs Uno: Final Say

The Arduino Mega is a serious upgrade from the Uno. If you need more than 20 input/output connections for your project, then the Mega is the board for you. It allows you to use the same controller to process over 30 serial communication devices.

Recommendation

I recommend the Arduino Mega vs Uno R3 for anyone who are designing advance electronics projects (such as drones, robotics or any requirements with greater than 20 pin connections). The micro-controller board is supported through an outstanding open-source system. If you encounter any problems, you could refer to the Arduino ecosystem for advice and suggestions.

Pros
  • Big – lots of I/O for projects that need it
  • Memory – if your code simply won’t fit in the Uno, you’ve got much more room here
  • Same/Similar shape/layout – many shields made for the smaller boards will still work
  • Nicely organized – I/O grouped by function
Cons
  • Big – not for your space-constrained project
  • Shield Compatibility – limited support for large I/O expansion header

Who’s the winner: Arduino Mega 2560 vs Uno?

The winner is the Arduino Uno. The Uno provides enough functionality to get a novice on his/her way to learning electronics and conducting less complicated projects.

The Mega appears to be the Uno on steroids. The board is made for more complex projects. It could potentially intimidate a newcomer with all the extra input/output pins.

Arduino Leonardo

Arduino LeonardoThe Arduino Leonardo is a microcontroller board based on the ATmega32u4 computer chip. It has 20 digital input/output pins. Seven of the pins can be used as PWM outputs and 12 as analog inputs.

The board has a 16 MHz crystal oscillator, a micro USB connection, a power jack, an ICSP header, and a reset button. To power the board, simply connect it to a computer with a USB cable. You can also use an AC-to-DC adapter or battery to get started.

The Leonardo has built-in USB communication. This feature eliminates the need for a secondary processor. Thus, Leonardo appears as a mouse and keyboard to a connected computer. It also shows up as a virtual (CDC) serial / COM port.

Power

The Arduino Leonardo can be powered via the micro USB connection or to an external power supply. The power source is selected automatically. External power can be supplied by an AC-to-DC adapter or battery.

Input and Output

The 20 digital input/output pins can be used as an input or output. You can use the functions pinMode(), digitalWrite(), and digitalRead() to assign the pins. They operate at 5 volts. Each pin can provide or receive a maximum of 40 mA.

Technology

The Leonardo uses the ATmega32u4 is a low-power CMOS 8-bit microcontroller based on the AVR enhanced RISC architecture. This device can achieve throughputs approaching 1 MIPS per MHz with the execution of powerful instructions in a single clock cycle. The system designer then can optimize power consumption versus processing speed.

The AVR core combines its 32 general purpose registers with a plush instruction set. Because all the registers are connected to the arithmetic logic unit (ALC), two independent registers can be accessed during a single clock cycle.

Communications

The Leonardo uses various facilities to communicate with a computer, another Arduino, or other microcontrollers. The ATmega32U4 supports UART TTL (5V) serial communication on digital pins 0 (RX) and 1 (TX).

The 32U4 provides serial (CDC) communication over USB and appears as a virtual com port to software on the computer. The chip performs the function of a full speed USB 2.0 device (using standard USB COM drivers). On Windows machines, an .inf file is required.

The Arduino software includes a serial monitor. This feature allows you to send simple textual data to and from the Arduino board. The RX and TX LEDs flashes when data is being transmitted via the USB connection to the computer. But, this feature is not active when serial communication occur on pins 0 and 1.

Automatic (Software) Reset and Bootloader Initiation

The Leonardo is designed to allow software from a connect computer to reset it. This feature eliminates the need to physically press the reset button prior to an upload.

The reset is triggered when Leonardo’s virtual (CDC) serial / COM port is opened at 1200 baud and then closed. When this happens, the processor will reset, breaking the USB connection to the computer. Thus, the virtual serial/ COM port will disappear. The bootloader starts after the processor resets. It remains active for about 8 seconds.

The bootloader can also be initiated by pressing the reset button on the Leonardo.
Please be aware that as the board powers up, it will jump straight to the user sketch rather than initiating the bootloader.

Because of the way the Leonardo handles reset, you should allow the Arduino software to initiate any resets before uploading any code. Remember, you can always press the reset button to start the bootloader if the software fails.

Arduino Mega vs Uno – Buyer’s Guide

Which is best for robotics?

The Mega is the best choice for robotic projects. It provides enough inputs and outputs to handle the requirements of the project.

Which is best for beginners: Arduino Uno vs Mega vs Leonardo?

Even the Arduino website shows both Uno and Leonardo for entry level users, the overall opinion of users is that beginners should start with the Uno.

Is this an original Italy made Arduino?

To ensure you have an original Arduino, check the label on the board. It will tell you if the product you received is a true Arduino.

Do they come with wireless module?

The Arduino Uno can come with a WiFi module integrated into the board. Online, users have shown that Bluetooth could be added to both the Mega and the Leonardo.

Conclusion

Both the Arduino Uno and Arduino Mega are excellent micro-controller boards. In fact, they mirror each other. The Mega is the grown-up version of the Uno.

In order to complete a project, you must know what components are needed to get the job done. If you new to electronics and want to learn the basics, the Uno is the board for you.

Damon Coleman

Entrepreneur, robotics fan. I have a Diploma in Technical Education, interested in robotics. My favorite platforms are Arduino and Raspberry Pi. Welcome to the world of robotics!

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