Microcontroller

First we looked at the architecture of a microprocessor:

ALU: Arithmetic Logic Unit: The "brain" of the microprocessor, reads the program and carries out the mathematical calculations necessary.

ROM: Read Only Memory - where the program is stored.  The type of ROM we are using is Electronically Erasable Programmable Read Only Memory, which means that to reprogram the microprocessor, all we have to do is connect is back to the computer and write over the old program with a new one.  Other chips may be once use only, meaning that if you make a mistake, or need to change a part of your program, you need to get a brand new chip.

RAM: Random Access Memory.  This is memory the microprocessor uses whilst the program is running.  The parts of the RAM are called b0 - b13.  You can ask it to remember any number, add and subtract, or count how many times a part of the program has been repeated.

Clock / Program Counter / Timers: Controls the speed of the mathematical calculations

I/O Ports: Connect the microprocessor to the real world so that we can control outputs and test inputs

Buses: Groups of wires which transport information from one part of the microcontroller to another.

Then we looked at the "Stamp Controller" we will be using for our programming.

To be able to use outputs with the Stamp Controller, we needed to add an output driver to boost the current from the microprocessor enough to drive output transducers like buzzers, motors and lamps.

There are two types of output driver.  The Darlington Pair at the top, which is used to drive anything which requires on/off control - lamps, buzzers; and the Push Pull driver at the bottom which is used to drive motors so that they can turn in both directions.  This means that a buzzer needs to be connected to one output pin, and a motor to two output pins - one to make it go forwards and one to make it go backwards.