CSE208W Lecture #1 Notes Barry E. Mapen

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1 CSE208W Lecture #1 Notes Barry E. Mapen Parts Kit Before we start, let s take a look at the parts kit. Open you kit when you have some time and start to learn what the pieces are inside of that kit. Be a little careful handling the parts since the pins tend to be rather sharp. There are several types of components in your kit. We cover these in some detail below. Each component has a shape that is the packaging. Components come in different shapes and sizes for different applications. As we go through this course, we will talk about other packaging options. For now, only worry about being able to identify the parts in your kit. Do not worry about memorizing the names of everything or how to read resistor codes. You can find most of the information contained in this document on the reference book link off of the main CSE208W page ( If you have questions, as always, please ask your TA or myself. Resistors Resistors in your kit come in two basic styles. The first is a single resistor in an axial package. Component Schematic Symbol These passive components are used to limit current to other components in your circuits. The colored bands on the resistor indicate the value in ohms. To read standard ceramic axial resistors look for the gold or silver band on the resistor. This is the last band; hold the resistor so this band is on the right when you are looking at the resistor. Reading from left to right, the bands are the 1 st digit, 2 nd digit, and the multiplier. The multiplier value is 10 to the color band value power. This is multiplied times the 1 st and 2 nd digit. For example, in the picture above, brownblack-red this is 10*10 2 = 1000Ω or 1k Ω. If we had a resistor of orange-orange-black it would be 33*10 0 = 33Ω. The following table shows the color codes and values of each band.

2 Color Value BLACK 0 BROWN 1 RED 2 ORANGE 3 YELLOW 4 GREEN 5 BLUE 6 VIOLET 7 GRAY 8 WHITE 9 To save on time and space, we will mostly be using the other type of resistor in your kit and is known as a SIP (single in-line package) resistor. This resistor contains a single common point connecting one side of all of the internal resistors. All of the other pins are the outputs of each resistor. This is shown in the following diagram. Reading the values off of these components is the same as above, except that instead of color bands, the manufacturer prints the three digits on the side of the device. The 1 st and 2 nd digits are printed with the multiplier following. For example 102 is really 10*10 2 = 1000Ω or 1k Ω, just like the brown-black-red resistor above. Component Schematic Symbol

3 Light Emitting Diodes (LED) These devices come in several packages and many colors. Essentially they are all the same. Component Schematic Symbol You will notice that one of the LED pins is longer than the other. This is the side that needs to go on the + side of the circuit. The other will go towards ground. One way to remember this is that the + has two bars that could be made into one long pin while the side only has one shorter bar (pin). The other way to determine the orientation of an LED is to look for the flat side on the plastic casing. This is the negative side. You will find that you need to take up a little extra room on your proto-board to work with the individual LEDs. If you think you will continue to build projects after this course, you may want to invest a few dollars in a set of bar LEDs. Chips The most common items in your kit are the integrated circuits (IC)s or chips. All of your chips are provided in dual in-line pin packages or DIP packages. To locate the top of the chip, look for the half circle notch at one end (shown left). Ignore any little holes that may appear elsewhere on the chip (shown right). The internals of these chips will be covered in detail during the next lecture, and the one chip you will be using for this weeks lab will be covered during the lab period. Component Schematic Symbol Depends on the specific chip see logic works for examples

4 Once you have located the top of the chip, the pins are counted starting at the top left and going down then from the bottom right going up. This is shown in the following diagram. In general (not always), the bottom left pin will be ground and the top right will be power. Once these two pins are connected, the internal logic can function. When you apply a signal to one of the input pins, the output will produce the expected logical result. If the input is floating (i.e. not connected) then the chip will output a random value. We will talk about this behavior later in the course. Electricity For this course, we will limit ourselves to a simplistic view of electricity and electrical components. One piece you need to remember is that a wire can only have one value on it at a given time. For example, if we connect a wire to +5, then the wire has a 1 on it. If we connect the wire to ground then it has a 0 on it. If we try to connect a wire to both power and ground, we will have a very hot wire! This is known as a short circuit. In logic works, connecting two different signals to a wire will generate a conflict and a binary probe will show this as C. The following diagram illustrates the input circuit you will be building. This configuration is known as a weak pull-up resistor on the input side. When switch is open, the value of the binary probe is 1. When the switch closes the value goes to a 0, not a C. Why? If we had connected power directly to ground, the two signals would be in conflict. In that case, we have equal amounts of + and -. Since we are running the +5 signal through the resistor, we have weakened it so when the switch connects to ground, the net result is the ground signal winning. To start in this course, you do not need to fully understand why this works, just be able to wire the schematic below and verify that it works during the first lab. Your switches are in a package of 8-DIP switches.

5 +5V Input Circuit 1 The other circuit you will be building in your output circuit. This circuit is used to provide enough power to light your LEDs. An LED requires about 15-20mA of current to light. Knowing that we have a 5V power supply we can use Ohm s Law (V=IR) to solve for the correct resistance so that we do not destroy our LEDs. 5V/.015A = 333Ω. This is close enough to 330 ohms, which is one of the SIP resistors provided in your parts kit. If you use the 1kΩ resistor, you may not have enough power to light up your LEDs, but you will not cause any damage. The short story for why we go through this process is that there is not enough current for any of the other chips in your parts kit to power an LED and another chip reliably. If you have some spare time and are curious, try it. You will not damage anything in your circuit, but you will probably find that the LEDs turn on and off incorrectly when you use your logic probe on the circuit or connect other chips to signals that are trying to power your LEDs. Output Circuit +5V Parts List 330 Ohms U LED 1 0 U1A

6 CSE208W Lecture #2 Notes Barry E. Mapen How the Proto-Board Works There are two types of strips on the proto-board. The first type is called a bus strip. This strip is used for running common signals all around the proto-board. For this course, we are using bus strips that have 2 rows. One will be used to carry power (also referred to as V CC, V DD, +5V, etc), and the other will be used to carry ground (also referred to as V SS, 0V, etc). The other type of strips on the proto-board is the component strip. These strips have a gap down the center of them dividing the left and right sides of the board. The 5 pins on the left are connected, and the 5 pins on the right are connected. There is no connection between the left and right halves. There is also no connection between rows. This allows you to plug in a chip and wire up each side of the chip without having the two sides short themselves out. Proto-Board Tips and Tricks Stickers for Switches You may find that you have difficulty remembering which way to flip your switches so that you can generate a 1 or a 0 when you are working hard on a lab. I recommend that you spend a few minutes and make sure that every switch on your proto-board works as expected. Then, take a sticker and label the switches as shown in the above picture.

7 Common Problems Power/Ground We are usually really excited about building our new circuit and quickly populate the board with the chips we will use. We then wire all of the logic together just as it is shown in the schematic we create. The problem is, our schematics are built using LogicWorks where we can just connect gates. On the proto-board, the gates are not active until the chip has proper power and ground. For the majority (not all) of the chips in your parts kit, power is the top-right pin (usually #14) and ground is the bottom-left pin (usually #7). Make sure these two pins are connected on your chip by placing your logic probe on the pin of the chip. If you have power and ground correct, then check for the next most common problem, an upside-down chip. Integrated Circuits (IC) Chips There are different classes of chips that we will be discussing. The simplest chips have discrete gates in them. This small-scale integrated logic (SSI) is the most basic building blocks we will use in this course. Example SSI parts are AND, OR, and NOT. As we move on in the course we will start to use medium-scale integrated logic (MSI) such as 4- bit adders, 8:1 multiplexors, etc. For now, do not worry about these MSI devices. Logic Families The integrated circuits come in different families. The families denote the physical properties of the chip including the voltage needed for the chip and how fast the chip can produce a result. The parts in your kit are from the LS family. You don t need to worry about the specifics of the different families, but you should know that not all chips with the same part number are the same. For more information read chapter 3 in your textbook, especially section 3.8 and 3.11 starting on page 135 and 166. When you are looking at your chips they will say something like 74LS00, or 74HC00, or 74F00, etc. Since we are only concerned with the logic and not the electrical properties at this time, we will refer to chips without their family. For example 74x00 would represent all of the preceding chips. Small-Scale Integrated Logic Since most SSI logic chips contain discrete gates, it is necessary to describe the varieties of gates within the parts. Most chips are described by the quantity of the gates in the package followed by the number of inputs to the gate. All discrete gates have a single output in your kit. For example, the diagram below shows a 74x32 chip or a Quadruple 2-Input OR Gates IC.

8 1 74x32 Vcc GND 8 This chip contains for independent OR gates. After power and ground are applied to the chip, you can connect two of your switches to pins 1 and 2 (inputs A and B). Then connect pin 3 (output Y) to one of the inputs of 74x05 (the output of this NOT gate connects to your LED do not connect pin 3 to the LED directly, it will not light up correctly). Toggle the switches and you should see the following results 74x32 A B Y You can click on the reference book off of the main CSE208W website and then click on Chip Data to get information about any specific chip in your parts kit. You can also go to the chip directory ( that contains information on virtually every chip ever produced. For this course, you will probably want to use the local reference book since we have provided a more compact list for you. Don t worry about memorizing the chip numbers and the gates contained within them. As you use the parts, the numbers will start to stick in your head. What you should do now is keep a sheet handy with your parts kit so you can identify the chips you need for projects during the rest of the semester.