Specifications

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2.2.3 Microcontroller
Microcontrollers are a programmable logic solution that provide a wide array of
embedded functionality. Essentially, they are an entire computer inside of a
single chip, providing reasonably accurate clock sources for timing, integrated
instruction RAM and program ROM, and an integrated CPU for mathematically
intensive operations. Microcontrollers are produced by several notable
manufacturers, and have a wide range of selectable options, such as additional
integrated components, communications buses, power consumption restraints,
as well as cost limits. The tools provided by the manufacturer offer the ability to
program the unit in either the machine assembly language, or a common high
level language such as C. Microcontrollers offer a lot of the positives relative to
both an FPGA, or an ASIC. The chips themselves are in fact a pre-designed
ASIC, offering a lot of features in a very small package, while consuming minimal
levels of power, at a reasonably low cost. With integrated program memory, they
offer a level of programmable functionality that while not allowing for custom
logical design at the hardware level, allows the microcontroller to be useful in a
wide variety of applications, albeit not nearly as fast for certain operations, such
as arithmetic and more intensive mathematical operations.
2.2.3.1 Microchip PIC18
The PIC18F is a low cost microchip that displays an ideal brain for the portable
unit. The PIC18Fcharacteristics enhances the data accuracy with a 10-bit
Analog-to-Digital converter. This would give the system an accurate reading that
will be used to display the information, computation, and data transfer. The
choice of this microcontroller is weight out on the output of the sensor. If the
sensor reads out a bulky reading then microcontroller would need to have been
able supply enough resolution to gain precise reading. The memory for this IC is
very efficient as well. It tops out at 2kybytes of RAM, which is very sufficient for
the algorithms and also the logic computation for the design. This design will
need as much memory as possible to approximate the correct value given by the
sensor. Given that, there will be data being transferred from the sensor to the
PIC microcontroller and to the display. The memory will be imperative to
optimizing the system to run at its highest performance. Figure 2.2.3.1 shows the
block diagram of the PIC18F.