Defcon Kaklkaklkekl (Wiki)

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====== Microcontroller concepts ====== ===== The difference of processors and controllers ===== A microprocessor is very generally speaking a processing device, with little to no supporting elements included on the device itself. Reduced to the basic microprocessor concept, it will be a device with an instruction set, controlling registres, general registers and processing units like Arithmetic Logic Unit (ALU), and finally external connections in form of data bus, address bus and interrupt pins. A microprocessor requires external component to implement memory (RAM), storage (ROM, FLASH) and for interfacing with I/O of various forms. A microcontroller integrates a microprocessor with several supporting elements in the same package. A microcontroller will typically include RAM, ROM and commonly FLASH memory, as well as I/O interfacing (digital ports, A/D converters, timers, PWM generators, serial UART) in a single package. The full data and address busses of the microprocessor is commonly not available as pins on a microcontroller. Instead, interfacing is done though the integrated I/O ports. The microprocessors can be constructed as very high-performance parts, and their nature is a very generalised one, allowing the microprocessor to be used in complex systems, or built into very special purpose ones. This generic nature means a microprocessor-based system will require many supporting systems physically external to the processor itself. These externals may be of very high-performance and may even be to some extent autonomous, offloading processing from the processor. This naturally comes at the cost of complex physical and electrical constructions. Compared to this, the microcontroller is typically relatively low-performance, and has a reduced and sometimes specialized instruction set. This is offset by the fact that a lot of I/O interfacing and supporting functionallity is built into the same package as the processing core. This allows for compact, simple physical and electrical designs, but limits the practical use of microcontrollers to embedded systems, and specialized control systems. Microcontrollers are excellent devices to use in control-systems because of their I/O bound nature, low parts count and realtive low price. When looking to construct a general-purpose and/or high-performance system, you are probably looking at using a microprocessor. On the other hand, when developing a dedicated control system, you will probably be using a microcontroller, and by that, reducing development time, complexity and cost. ===== Families of microcontrollers =====