Specifications

Chapter 1 - Introduction to Microprocessors
Of course, when this happens with a computer, we simply reset it and it will keep working.
However, there is no reset button we can push on the microcontroller and thus solve our
problem. To overcome this obstacle, we need to introduce one more block called watchdog. This
block is in fact another free-run counter where our program needs to write a zero in every time
it executes correctly. In case that program gets "stuck", zero will not be written in, and counter
alone will reset the microcontroller upon achieving its maximum value. This will result in
executing the program again, and correctly this time around. That is an important element of
every program to be reliable without man's supervision.
1.8 Analog to Digital Converter
As the peripheral signals usually are substantially different from the ones that microcontroller
can understand (zero and one), they have to be converted into a pattern which can be
comprehended by a microcontroller. This task is performed by a block for analog to digital
conversion or by an ADC. This block is responsible for converting an information about some
analog value to a binary number and for follow it through to a CPU block so that CPU block can
further process it.
Finnaly, the microcontroller is now completed, and all we need to do now is to assemble it into
an electronic component where it will access inner blocks through the outside pins. The picture
below shows what a microcontroller looks like inside.
Physical configuration of the interior of a microcontroller
Thin lines which lead from the center towards the sides of the microcontroller represent wires
connecting inner blocks with the pins on the housing of the microcontroller so called bonding
lines. Chart on the following page represents the center section of a microcontroller.
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