Defining the microcontroller

Breaking it down

What is the application?

Bit Size? 8-bit, 16-bit and 32-bit

Taking a look at the different architectures and what they mean (ARM/AVR/PIC/8051)

RISC and CISC architectures

ARM

AVR

PIC

8051

The Operating Voltage

Package Size

Which communication interfaces are needed?

How much memory is needed?

Comparing microcontrollers

Rule of thumb tips on picking a microcontroller

Conclusion

or in comments below. Be sure to check out the other blogs in this series:

how to select a capacitor

,

resistor

,

inductor