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If you connect the red and green wires as shown in the picture you will be connecting positive power (5 volts) and ground to your chip. It is a good habit to use specific color wires for specific
purposes. Common practice it to use red for 5 volts (commonly referred to as VCC), green for ground and other colors for your inputs and outputs. By sticking to this scheme, problems will be easier to
spot if the design doesn't work when finished. There is plenty of extra wire and cutters in the lab so you can make any length wires you desire.
Xilinx ISE Series Software
Xilinx is an international company that produces programmable logic. They are the largest producer of programmable chips in the world. Xilinx produces a software package called ISE. At this
point, it is important for you to understand that the ISE software will be used to create projects using a coding scheme similar to C++ called VHDL. The ISE software will allow you to create projects.
The simulation part will then be implemented through a software package from Mentor Graphics Corporation called ModelSim. Simulation is important in that it will allow you to be able to verify that your
project is working correctly before you transfer your design onto a final product or chip.
To help students get started with the software, a very "simple" project has been created that will step
through the initial concepts of project creation and simulation. Its purpose is to introduce the software and some of its features. This software is extremely powerful, extremely expensive, and it
is impossible to think you will master all of its features in one course. Our desire is to introduce a variety of projects utilizing some of the many different capabilities of this software. Remember
what is contained in these labs so you can reference back to them when you are in future courses. All of these projects have VHDL code as a central theme.
Internet Students
Purpose
The purpose of this lab is to introduce some of the features of the WinBreadboard (or MacBreadboard).
Some Features of Winbreadboard
1. The power switch is at the middle
left on the screen. Leave it in the off position until you are ready to simulate the circuit. The circuit cannot be modified unless the power switch is in the off position.
2. Sources for +5 Volts and
Ground are just above and below the power switch. A common way to route power is to connect (run a wire) from the +5 volt output to the very top row of connections. All connections on the top row are connected
together. Similarly, connect ground to the very bottom row of connectors, which are also all connected together.
3. Switches for the inputs are located near the top of the screen. For inputs A, B, C, and D,
either the true or the complementary values of the switch setting can be obtained. These are marked below the switch. To the right of these switches is an area in which you can specify the meaning of each input.
Where the inputs have an order associated with them, make the left-most switch be the most significant. Only the true values of the switch settings can be obtained for inputs labeled E through L.
4. When a chip
needs to be placed on the board from the menu, the chip is positioned to straddle the middle line. All of the five connections placed vertically are connected together. When a chip is placed on the board, it
uses one of these connections, so don't try to use it again to connect a wire to this pin. Connections between various elements on the board are made with jumper wires.
5. The board has 4 LED's located at the
bottom, which are used to monitor important points of the circuit, e.g., the circuit outputs. They light for true and stay dark for false. The point to be monitored should be connected to the + side of the LED and
the other to ground. As with the switches, make the left-most LED correspond to the most significant bit where appropriate.
6. Information on the internal connections of the IC chips can be found by clicking on
"Chip Schematics" on this or any other of the lab pages. Assume that you are looking at the top of the IC chip with the half-circle indent at the left (sometimes there is a dot at this end
also). Then the chip inputs are numbered with 1 at the lower left. Pins are numbered counterclockwise from 1 to the maximum number. Thus for a 14-pin chip, 1 and 14 are across from each other and 7 and 8
are across from each other. See one of the chip schematics for an example. (Often, but not always, pin 7 is ground and pin 14 is power for a 14-pin device.
7. Later on the clock will be needed. It is
located in the upper left corner of the board. Clock frequency and mode of operation are both variable that can be set. More will be said about this later when sequential circuits are discussed.
8. If all
the same colored wires are used, it will be hard to trace the circuit. Therefore, it is recommended to standardize the color used for particular wires. The conventional color for +5 volts is red and black is
used for ground. A shared color should be used for outputs, another for inputs, and another for interconnections. Sometimes a different scheme may prove more useful, e.g., making the parts of a circuit
associated with a particular memory element (flip-flop) have the same color. Note: The menu allows the user to choose whether wire length or connection determines the color of the
wire. For use in this class, it is suggested that wire connection be selected to determine the wire color. Set this menu item before doing anything else.
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