Specifications

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programming languages that this task can be accomplished in include Assembler, C,
and BASIC.
Another function that the microcontroller could perform would be the power usage and
battery charge state calculations. Taking input from sensors connected to the charge
controllers of the incoming power supplies, the microcontrollers would be able to
monitor all incoming power. Next, the microcontroller would be able to measure the
amount of energy being used within the entire system. This information could then be
fed to the LED display, informing the user of the power usage and how much time the
battery has left while running any applications hooked up to the system.
There are a couple attractive qualities of microcontrollers that make them a realistic
component to include in our design. One such aspect is the fact that microcontrollers
are relatively cheap; ranging from $1 to about $15 for low level microcontrollers. At this
price, it is extremely easy for our group to budget for one or multiple microcontrollers if
needed. Also, since microcontrollers are relatively small, our design will not be altered
drastically by the addition of one or more microcontrollers.
In selecting our microcontroller, there are a few aspects that we have to take into
consideration for our design. First off, the microcontroller should be easily
programmable. This will help us avoid wasted time on a microcontroller that is more
difficult than necessary to program. Also, as the needs of our LED display will
undoubtedly change during the testing phase, it will be necessary for the microcontroller
to be reprogrammable, and not a one-time programmable chip. Finally, we will need to
be sure to pick out both a microcontroller and an LCD display that are compatible with
one another.
In our research, it is necessary to look at several of the available microcontrollers side
by side so that we may choose one that is most ideal for our uses. With the plethora of
information regarding the many different microcontrollers we have to choose from, it
should be an easy task to find one that suits our needs. Below, we will discuss in detail
the microcontrollers that we looked at in our research and which one we will ultimately
be using in our final design.
Texas Instruments provides a family of microcontrollers known as the MSP430 line.
These 16-bit RISC mixed-signal processors are ideal for taking measurements in
battery-powered devices. As it is our desire to monitor the power supply remaining in
our battery, this feature of the MSP430 microcontroller would prove extremely useful.
The power drawn by the MSP430 while active is around 120 µA/MHz @ 2.2 V, and dips
down to 0.7 µA/MHz @ 2.2 V or lower while inactive. This low power consumption
would work well with our design, as we would not need to worry about it drawing too
much power away from the laptop and projector that we will be powering.
The MSP430 is also user-friendly, easy to learn, and can be programmed in C. Since
Texas Instruments offers over 230 parts for the MSP430 line, there will undoubtedly be
a specific part that is ideal for our needs. The MSP430 has a built in clock system and