ELM413

Elm Electronics – Circuits for the Hobbyist

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Pin Descriptions

Ordering Information

These integrated circuits are available in either the 300 mil plastic DIP format, or in the 200 mil SOIC surface

mount type of package. To order, add the appropriate suffix to the part number:

300 mil Plastic DIP............................... ELM413P

200 mil SOIC..................................... ELM413SM

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All rights reserved. Copyright ©1999 Elm Electronics.

Every effort is made to verify the accuracy of information provided in this document, but no representation or warranty can be

given and no liability assumed by Elm Electronics with respect to the accuracy and/or use of any products or information

described in this document. Elm Electronics will not be responsible for any patent infringements arising from the use of these

products or information, and does not authorize or warrant the use of any Elm Electronics product in life support devices and/or

systems. Elm Electronics reserves the right to make changes to the device(s) described in this document in order to improve

reliability, function, or design.

This pin is the positive supply pin, and should

always be the most positive point in the circuit.

Internal circuitry connected to this pin is used to

provide power on reset of the microprocessor, so

an external reset signal is normally not required.

Refer to the Electrical Characteristics section for

further information.

AuxOut (pin 2)

This is an output signal for gating auxiliary circuits

off and on. It is set to its active high level after the

trigger input has been at a high level for the time

determined by W1 and W0. It is forced low if the

trigger input drops below the lower threshold.

W1 (pin 3), and W0 (pin 4)

These are the two digital input pins that are used

to select the warmup period as shown in the chart

on page 1.

Trigger (pin 5)

This is a schmitt trigger input that is used to

initiate the circuit activity. A rising (low to high)

edge at this pin will cause the red LED to go off,

the green LED to become active, and the warmup

timer to begin timing. Once initiated, pin activity is

ignored until the warmup period is complete.

Green (pin 6)

This output pin signifies the power on (trigger

above the threshold) condition. It becomes

active once the threshold is exceeded, and

remains so until the trigger resets and the

warmup period is complete.

During the warmup period, this output will flash if

either the 1 second or the 5 second time is

selected. Flash rates are nominally 2 Hz and 1

Hz respectively. For the 0.1 and 0.5 second

periods, the pin remains at a constant high level.

Red (pin 7)

This is the red LED drive output. It will be at a

high level when the circuit is at idle and the

trigger input is a low level. At all other times, this

pin is at a low output level.

Circuit common is connected to this pin. This is

the most negative point in the circuit.

ELM413DSA