Lab 3 page 1 ENT-DIGI-210 Lab 3 Notes ©Paul Godin Updated September 2007

Lab 3 page 2 Digital Logic Chips Basic Chip Configuration

Lab 3 page 3 Basic Digital Chips ◊Digital logic devices are usually in a familiar chip format, although sometimes can be found in a different package style. ◊The chips are often identified with a manufacturer logo, a part number or model number, and additional information about the manufacturing or other details.

Lab 3 page 4 Basic Digital Chips ◊A standard series for basic logic devices start with numbers 74, 4, or 14. ◊Examples ◊7404: inverter chips ◊7408: 2-input AND ◊7432: 2-input OR ◊4081B: 2-input AND

Lab 3 page 5 Basic Digital Chips ◊The naming structure (nomenclature) of the devices differs between manufacturers but most follow a common practice for naming their devices (this is called a defacto standard). ◊Manufacturers publish nomenclature information on their web sites.

Lab 3 page 6 Chip information Information on this IC: Second Line= Device Description DM 74 = Device Family 08 = Device Type N = Packaging (moulded DIP) First Line = Manufacture Information M = Wafer made in USA P = Assembled in Malaysia 9 = last number of year 03 = month of manufacture 0V = Die Run Code National Semiconductor ( Other information available from

Lab 3 page 7 Chips ◊Basic logic chips often come in 14- pin DIP packages, but package sizes and styles vary. (DIP = Dual In-line Package) ◊Pin 1 is typically indicated with a dot, half-circle, cut corner, sloped edge or other indicator. It’s important to check the specification sheet. ◊Numbers are read counter- clockwise from pin 1 (viewing the top of the chip) Pin 1 Pin 7 Pin 14 Pin 8

Lab 3 page 8 Chips – Specification Sheet Diagram from Voltage Ground The voltage and ground pins must be connected for the device to function. Check the specification sheet for the Vcc and GND pins.

Lab 3 page 9 Logic Diagram Labels

Lab 3 page 10 Labelling a Diagram Step 1: Design the circuit Step 2: Add component labels Changing the component labels in EWB: Right-click on the component Select “Component Properties” Choose: “Display” to remove extra labels “Label” to add a label “Value” to change the label on a switch

Lab 3 page 11 Labelling a Diagram (continued) Step 3: Look up the IC specification and its layout. The IC for the AND gate is a 74LS08 Match the logic diagram to the package. Diagrams from Logic Diagram Package Diagram AND gate #1 Inputs are pins 1 and 2 Output is pin 3. Vcc is pin 14 GND is pin 7

Lab 3 page 12 Labelling a Diagram (continued) Step 4: Add Pin Numbers to the diagram Adding labels in EWB: Select menu “M”, then “A”

Lab 3 page 13 Chip label U1:1 where: U1 is the chip :1 is the number of the gate within the chip Labelling a Diagram (continued) Step 5: Add chip labels and Vcc/GND pins

Lab 3 page 14 Example of a Properly Labelled diagram

Lab 3 page 15 Wiring the chip Vcc IN OUT

Lab 3 page 16 Steering or Control Gates

Lab 3 page 17 Introduction ◊An application for a logic circuit is to control one digital signal with another digital signal. ◊The AND and the OR gates can function as signal Control, or Steering Gates.

Lab 3 page 18 Control Gates Worksheet (AND, OR) ControlSignalYStatus ControlSignalZZ’Status Control Signal Y Z Z’

Lab 3 page 19 Proper Wiring “My circuit doesn’t work and I can’t find the error.” “Can you help me? Please?”

Lab 3 page 20 Features of a properly-wired circuit RED reserved for Vcc connections BLACK reserved for GND Connection Wires routed around the IC Wires the proper length Wires routed along horizontal and vertical plane Little or no exposed conductor IC is fully visible and accessible

Lab 3 page 21 Can you find the errors in this circuit?

Lab 3 page 22 Exposed conductors Short Circuit Bent Contact Wires routed over component Wrong color (shouldn’t be black or red) Wire too long Wrong color (should be black) Wires not on vertical or horizontal plane

Lab 3 page 23 Wire Tips ◊Use properly-adjusted wire strippers only (not cutters or teeth). Stripping must not affect the conductor in any way (scrapes, cuts or nicks). ◊The strip length should the height of the breadboard minus approximately 2 mm. ◊If wires are too short, there may be poor electrical contact. ◊If the wires are too long there is risk of a short circuit. END