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Usb power to busses

show power from pins 1 and 14 on the Launchpad to the + and - busses
Notice the color choice of wires. For the rest of the construction process, the short green and blue wires are only used for connections to GND and Vcc respectively.

5) connect your switches to gnd

Use the green jumper wires to connect the other side of your switches to GND (the blue bus). Yes, the switch pack is upside down . This is an intentional design decision that has to do with the pull-up configuration of the MSP430 Launchpad Hardware. With the switch pack upside down, flipping the switch "up" will register a "1" and flipping them "down" will register a "0" like you would expect. See the explanation below for more information, or just take it on faith that it works this way.

Switches to gnd

connect the open end of the DIP switch to VCC

You may notice that turning the switch on connects it to GND, but turning it off connects it to nothing! This can be really bad in a circuit- the values read from the GPIO pins will be essentially random! Ideally, you would want your switches to be "1" when up and "0" when down. To accomplish this, you can either use more expensive dual pole switches that switch between two connections instead of closing or breaking just one, or use what's called a pull up (or pull down) resistor. This is a resistor of large resistance connected to the rail you want the switch to read when it is open. The GPIO sees most of the connected voltage when the switch is on (and in digital applications most is enough), but sees the other rail when the switch is open.

"But I see no resistors in the picture"-- you're right! The MSP430 has pull up resistors built in- we just have to enable them when we configure the GPIO pins. You'll learn more about that in part II of the lab.

6) connect vcc and ground to ics

The BCD decoder is an active piece of circuitry, so it needs a power connection to work properly. Connect Vcc to pin 16 (lower A-E column 21) and GND to pin 8 (lower F-J column 28) .

The display also needs a common connection to ground (since it is common cathode type). Connect pin 3 (lower F-J column 38) to GND. The display is just a package of individual LED's in parallel connected to one common ground point.

Lastly, there are some options (dealing with latching and enabling) on the decoder we want to permanently set in our circuit. Connect Vcc to pins 3 and 4 (lower F-J columns 23 and 24) and GND to pin 5 (lower F-J column 25).

Power connections for circuit components

shows Vcc to decoder pins 1, 13, and 14 and ground to decoder pins 9 and 12 and display pin 8
Notice how the color scheme of blue jumpers for Vcc and green jumpers for GND continues here. It's good practice to use a consistent color scheme for Vcc and GND since they can fry your chips if mis-applied.

7) connect the decoder to the resistor arrays

Our resistor arrays

The resistor arrays used in this class contain 4 isolated 470 ohm resistors. We could have just as easily used individual resistors, but this keeps the breadboard clean and prevents accidental shorting from the uninsulated resistor leads. Every pair of pins in the strip works as if there is a 470 ohm resistor in between them, but each pair exists on its own. I.E. there is a resistor in between pins 1 and 2 but nothing between 2 and 3.

Questions & Answers

a perfect square v²+2v+_
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Abdirahman Reply
algebra 2 Inequalities:If equation 2 = 0 it is an open set?
Kim Reply
or infinite solutions?
Kim
y=10×
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if |A| not equal to 0 and order of A is n prove that adj (adj A = |A|
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rolling four fair dice and getting an even number an all four dice
ramon Reply
Kristine 2*2*2=8
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Differences Between Laspeyres and Paasche Indices
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No. 7x -4y is simplified from 4x + (3y + 3x) -7y
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is it 3×y ?
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J, combine like terms 7x-4y
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f(x)= 2|x+5| find f(-6)
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f(n)= 2n + 1
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Need to simplify the expresin. 3/7 (x+y)-1/7 (x-1)=
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. After 3 months on a diet, Lisa had lost 12% of her original weight. She lost 21 pounds. What was Lisa's original weight?
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preparation of nanomaterial
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Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
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Prasenjit Reply
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
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the Beer law works very well for dilute solutions but fails for very high concentrations. why?
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Source:  OpenStax, Intro to computational engineering: elec 220 labs. OpenStax CNX. Mar 11, 2013 Download for free at http://cnx.org/content/col11405/1.2
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