Playing around with the development boards and gadgets I was wondering about the differences between Microcontrollers (MCU) and Microprocessors (MPU). I found a nice concise and informative article (link in the resources section). For me the highlights of the document and the comparison drawn bettern MCU and MPU are:

• MCU uses on-chip embedded memory, this leads way to a short start-up period. Downside of embedded memory is that there is limited space. MPUs use external memory.
• MCUs need one single power rail whereas MPUs need several (for core, DDR etc.)
• MPUs have much more processing power than MCUs. A full operating system’s requirements are more likely to be met by MPUs.
• For numeric-based (number-crunching scientific type) applications and heavy user interfaces MPUs are more suitable
• MCUs consume far less power than MPUs

So in a nutshell, MCUs are generally a better choice for low-cost, low-power projects. For example, for small devices like remote controls, smart meters MCUs are preferred.MPUs perform much better in more resource-demanding systems.

Resources

• Atmel article