Industrologic LED4N

4 character LED numeric display

Reference Manual

version 06/27/06

Industrologic, Inc.
3201 Highgate Lane
St. Charles, MO
63301
USA

Phone: (636) 723-4000
WWW: http://www.industrologic.com
Email: info@industrologic.com

Trademark and Copyright Information

LED4N is a Trademark of Industrologic, Inc. 2006
This document is Copyright (c) 2006 by Industrologic, Inc.
All rights reserved.
No part of this manual may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying or scanning, for any purpose other than the personal use by the purchaser of this product. Industrologic, Inc. reserves the right to revise this document at any time without obligation to notify any person of such revision. Industrologic, Inc. assumes no responsibility for any errors that may appear in this document.

Warning/Disclaimer

Whereas effort has been made to make the information in this document as useful and accurate as possible, Industrologic, Inc. assumes no responsibility for the application, usefulness, or completeness, of the information contained herein. Under no circumstance will Industrologic, Inc. be responsible or liable for any damages or losses including indirect or consequential damages or losses arising from either the use of any information contained within this manual or the use of any products or services referenced within this manual.

Industrologic, Inc. reserves the right to change any product's features, specifications, documentation, warranties, fee schedules, and conditions at any time and without notice.

Industrologic products are provided as printed circuit board level assemblies. Some Industrologic products may include mechanical packaging assessories which are provide for the purchaser's convenience, and are not intended to be final assembly enclosures.

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Warranty

Industrologic, Inc. products are warranted to be free from defects in workmanship or material under normal use and service for a period of one year from date of purchase. Industrologic's warranty is to the original purchaser only, but is extended to you by the Distributor or OEM from whom you purchased the product.

Industrologic's obligation under this Warranty is limited to replacement with a new or repaired unit to the original purchaser. The unit must be returned, and replacements obtained from Industrologic, Inc. or the Distributor or OEM from whom it was purchased.

This warranty will not apply if, in the judgment of Industrologic, Inc., damage or failure of the product has resulted from accident, alteration, misuse, abuse, connection to or operation with incompatible signals or power sources, or improper installation.

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Return and Repair Policy

Products purchased in single piece quantities may be returned, if in resellable condition, for a full refund of the purchase price only, to the original purchaser, within 30 days of purchase.

Products must be returned by original purchaser with a Return Materials Authorization (RMA) number issued by Industrologic, Inc. or the Distributor or OEM from whom it was purchased, authorizing its return. Current repair or replacement fees and procedures will be related during the issue of the RMA number.

Warranty or repair units must be returned with postage and insurance paid by purchaser. Industrologic, Inc. is not responsible for damages or loss during shipment.

Industrologic LED4N

4 character LED numeric display

The Industrologic LED4N is designed to provide an easy to interface and easy to program 4 character numeric LED display for nearly any microcontroller or Programmable Logic Controller (PLC).

Summary of Features

Based on a 4-digit 7 segment "clock stick" LED display, with red 0.4 inch height numbers, a decimal point for each number, and a clock style colon.
Microcontroller controlled display segments with character sets for numeric and selected alpha characters, as well as selected punctuation.
Requires only +5 and ground power connections, and 2 logic level outputs from the circuit driving the display.
Uses an extremely simple protocol that can be easily created on nearly any microcontroller board or Programmable Logic Controller (PLC).

Mechanical Specifications

Double-sided .062" FR-4 glass epoxy printed circuit board.
Board assembly has four #4 clearance holes available for mounting to an enclosure or standoffs, but is light enough to be mounted with only the two holes closest to the display module.

Electrical Specifications

Power supply requirements-
Power supply voltage: 4.5 to 5.5 volts regulated DC
Power supply current (no LED segments turned on): 6 mA at 5V
Maximum power supply current: 70 mA at 5V

Operating environment:
Temperature: 0-50 degrees Celsius (32-122 Fahrenheit)
Humidity: 30 to 80 percent, non-condensing

Logic level control signals (digital inputs)
Enable: 10K pull-up resistor to +5, sink current 0.5mA
Clock: Microcontroller internal current source, sink current 0.1 mA

Connecting the LED4N to Power and Control Signals

The LED4N is normally powered by a +5 volt source of power on the Industrologic product, microcontroller board, or other digital device that is manipulating the control signals. It is the user's responsibility to insure that the +5 supply provides enough current for the LED4N.

The Enable and Clock control signals are microcontroller I/O pins configured as digital inputs, and can be driven with any 5 volt logic level digital outs from nearly any logic family, including most I/O pins of microcontrollers that are powered by 5 volts. The control signals are initialized to the logic "high" level, and are asserted with logic "low" levels.

Control Signal Operation

The LED4N uses an extremely simple protocol that can be easily created on nearly any Industrologic microcontroller based product, microcontroller board, or Programmable Logic Controller (PLC). The following is a description of the protocol and how to display characters on the LED4N. This text description may be all that is needed to understand how to use the LED4N, but if more detail is needed, refer to the following section on control signal timing.

The protocol consists basically of turning on an Enable signal, sending a number of Clock pulses to specify a character, and then turning off the Enable signal.

The first four groups of Clock pulses specify the four digits of the display. The fifth group specifies which decimal point to turn on, 1 for the first digit, 2 for the second, 3 for the third, 4 for the fourth, or 0 for none. The sixth group specifies whether to turn on the colon, with a count of 1, or off with 0. The delays specified between some of the control signals may not even be necessary using some programming languages, or on some microcontrollers, because the time required to send an instruction may be long enough to not require the delay.

The LED4N Display Sequence

1. Apply power to the controlling microcontroller or circuit and to the LED4N.
2. Initialize both Enable and Clock high.
3. Wait for 1/2 second for the LED4N to initialize after power up. (The LED4N will turn on all segments when powered up, and will then clear the display after 1/2 second.)

To reset the display:
4. Set the Clock signal low.
5. Wait 1 millisecond (1/1000th second).
6. Set the Clock signal high
7. Wait 1 millisecond before proceeding.

To set digit 1 (the leftmost digit):
8. Set the Enable signal low.
9. Wait 1 millisecond.

Send the number of Clock pulses that correspond to the number you wish displayed. (If this number is zero, do not send any Clock pulses, if it is one, send 1 Clock pulse, etc.) Refer to the LED4N Character Set on a following page to determine how many Clock pulse to send.

Clock pulses consist of the following:
10. Set the Clock signal low.
11. Wait 10 microseconds (1/100,000 second)
12. Set the Clock signal high.
13. Wait 10 microseconds.

After the Clock pulses have been sent:
14. Set the Enable signal high.
15. Wait 10 milliseconds before sending the next character.

Repeat steps 8-15 for digit 2.
Repeat steps 8-15 for digit 3.
Repeat steps 8-15 for digit 4.

Repeat steps 8-15 to specify the decimal point.
Repeat steps 8-15 to turn the colon on or off.

Control Signal Timing

The following timing diagrams detail the LED4N control signals if it is necessary to program the source of the signals close to the speed limitations. If the control signals will be in the logic level "high" state by the time the LED4N is initialized, the "reset" command may not be required. However, it is good practice to use it before each group of six display commands to insure the display is synchronized with the expected commands.

LED4N Character Set

The following is a chart of the numbers, characters, and punctuation available to be displayed on the LED4N, along with the (D)ecimal and (H)exadecimal number of low-going Clock pulses required to display each of these characters.

The first four groups of Clock pulses specify the four digits of the display. The fifth group specifies which decimal point to turn on, digit 1-4, or 0 for none. The sixth count specifies whether or not to turn on the colon, using 1 or 0.

Forming Words with the LED4N

The following demonstrates how a seven segment display, even though it is designed to display only numbers, can display a number of characters of the alphabet, and can approximate a number of others in order to form a number of words.

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