A hardware block diagram is one way to approach this task, often starting with the communication interface. UART, USB, I2C, and SPI are among those likely to be used by a microcontroller.

Embedded World — Nuremburg, Germany -- February 23, 2015 -- A new 16-bit 80251 microcontroller IP core shipping now from CAST, Inc. runs 69.7 times faster than the original 8051 chip, making it the ...