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Author Topic: mega 2560 vs uno  (Read 16085 times)
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i'm new to arduino and want to know which one is better...the arduino uno or the arduino mega 2560....please help....
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The Uno is cheaper.

The Mega2560 is bigger both physically and in terms of available FLASH memory and RAM (256kB FLASH/8kB RAM vs. 32kB FLASH/2kB RAM on the Uno)

The Mega2560 has more hardware serial ports, more timers, and more I/O pins.

Some shields do not work on the Mega2560 because the SPI pins and I2C (TWI) pins are not in the same place as on the Uno.

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So which one do you recommend..for common purposes..
I basically want to connect a 6 channel flysky transmitter to the board...
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For common purposes the Uno is a good place to start.

Though you should verify the connections to your flysky transmitter and make sure it's going to work. Finding others that have made this specific connection would be good.

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can you tell me the drawbacks and plus points of the uno and the mega 2560....
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can you tell me the drawbacks and plus points of the uno and the mega 2560....
That information was in the first reply to your post.  Why repeat?
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Some shields do not work on the Mega2560 because the SPI pins and I2C (TWI) pins are not in the same place as on the Uno.

and why didn't keep that part the same so ALL shields work??? they could have improved the board all the wanted, but just worked around that so that new shields and old shields would be compatible..
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and why didn't keep that part the same so ALL shields work??? they could have improved the board all the wanted, but just worked around that so that new shields and old shields would be compatible..

All engineering decisions have trade-offs.  No matter how good you think a trade-off is, it will annoy someone.

The SPI and I2C functions on the ATmega chips are done in hardware, so they have physical pins associated with them.  The physical ports for those pins are different on the ATmega328 (used in the Uno) and the ATmega2560 (used in the Mega).  To keep pin assignments clean (it is a clever way the Arduino library maps "Pin 1" to a pin on the ATmega chip), it was decided to leave the SPI and I2C functions on the native pins of the microcontroller.  This made hardware layout simpler and it made software implementations for functions like digitalRead/Write much easier (and faster).

Some thought was put into making shields compatible.

The ICSP header is in the same place on both boards and that header duplicates the pins used for SPI.  So if the shield uses the ICSP header for SPI (like the Ethernet shield) then this isn't an issue.

The latest revisions of Arduino boards have dedicated I2C pins on the headers.  
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