Arduino clone broad, UNO not be able to download ? missing the DTR reset this is not good design anyway ...

Only 5V pin, IOREF, and AREF voltage pins are connected. (Vin and 3.3V are not). Speed is 16MHz. Based On ATMEGA328-PU How to use: Set the fuses to arduino fuses Use SPI (ICSP) programmer and load the ...

The Uno also has a limited number of pins, making it difficult to work with when the project requires plenty of input and output components. However, these two areas are where the Arduino Mega shines.