Download Basic Digital Logic Lab 2 Notes

BXST-DIGI-210
Lab 2 Notes
©Paul Godin
Lab 2 page
Updated December
2014
1
Basic Switch Configuration
Lab 2 page 2
Definitions
◊ Pole: the arm or lever that moves when the
switch is thrown.
◊ Throw: the number of contacts a pole can
connect to.
Pole
Throw
Lab 2 page 3
Definitions
SPST (Single Pole Single Throw)
Pole
Throw
SPDT (Single Pole Double Throw)
Throw #1
Pole
Throw #2
Lab 2 page 4
Common
◊
◊
The common of a switch is the hinge point of the pole. It
is typically identified with a “C”.
It is called the common because it is the only point that
makes an electrical connection with the other points.
Throw #1
Common
Pole
Throw #2
SPDT (Single Pole Double Throw)
Lab 2 page 5
Switch
◊ DIP switch
◊ SPDT (Single Pole
Double Throw)
◊ Commons are labelled
◊ Internal wiring of the
DIP switch
Lab 2 page 6
LED Basics
◊
◊
◊
Light Emitting Diodes are a semiconductor that will
produce light if the anode (+) is more positive than the
cathode (-). It will block current in the other direction.
LEDs need current limiting (resistor) in series otherwise
the device will burn out.
They have minimum and maximum voltage ratings.
+
Anode
Cathode
Logic symbol for an LED
+
Anode
Cathode
Physical LED
Cathode is on flat side
Lab 2 page 7
Digital Logic Chips
Basic Chip Configuration
Lab 2 page 8
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 2 page 9
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
7411: 3-input AND
7432: 2-input OR
4081B: 2-input AND
Lab 2 page 10
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 2 page 11
Chip information
Information on this IC:
National Semiconductor
First Line = Manufacture Information
(manufacturer-specific)
M = Wafer made in USA
P = Assembled in Malaysia
9 = last number of year
03 = month of manufacture
0V = Die Run Code
(http://www.advanced-tech.com/ic_logos/ic_logos.htm)
Second Line= Device Description
DM 74 = Device Family
08 = Device Type
N = Packaging (moulded DIP)
Other information available from
http://www.ti.com/lit/an/snoa039c/snoa039c.pdf?keyMatch=marking%20conv
ention&tisearch=Search-EN
Lab 2 page 12
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.
◊
Pin 14
Pin 8
Pin 1
Pin 7
Numbers are read counterclockwise from pin 1 (viewing
the top of the chip)
Lab 2 page 13
Chip Labels
The IC specification and its layout in the specification
sheet may look similar to the image below where:
•A logic diagram uses labels
•These labels are matched to the physical package.
Logic Diagram
Package Diagram
1
2
3
4
Diagrams from http://www.ti.com
Lab 2 page 14
Wiring a chip
Vcc
IN
IN
OUT
Vcc
Lab 3 page 15
Chips – Specification Sheet
Voltage
Ground
The voltage and
ground pins must be
connected for the
device to function.
Check the specification
sheet for the Vcc and
GND pin numbers.
Diagram from http://www.ti.com
Lab 2 page 16
Example of a properly
wired chip in a
breadboard.
End
Lab 2 page 17