ELM711
Pin Descriptions
VDD (pin 1)
PB (pin 4)
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 internal microprocessor, so an
external reset signal is not required. Refer to the
Electrical Characteristics section (page 3) for further
information.
This pin is for the connection of a momentary action
pushbutton switch. Each press of the switch should
connect this pin to circuit common (VSS).
If the outputs are on, a momentary pressing of the
switch will change the LED pattern to the next
available one (there are eight in total). If the button is
pressed for more than 2 seconds, the circuit will turn
off all of the outputs. If the outputs are off when the
switch is pressed, the circuit will turn itself on with
the pattern set to the one that was in effect when the
circuit was turned off.
Blue, Red, Yellow, and Green (pins 2, 5, 6, and 7)
These outputs are used to control four different
groups of LEDs. The colours mentioned are only for
pin identification, and you can connect the actual
colours as you wish (none of the patterns require a
specific colour).
This input is internally ‘debounced’ and has an
internal pullup resistor to simplify the direct
connection to mechanical switches. Should you
prefer to use a logic signal rather than a switch, this
can be easily done, as the input will accept standard
TTL and CMOS logic levels.
Each pin outputs a high level (VDD) when ‘active’ or
‘on’. Note that Pulse Width Modulation (PWM)
techniques are used by a few patterns to control the
intensity of the LEDs, with a minimum pulse width
period of about 1 msec. For this reason, the ELM711
should not be used with mechanical relay circuits.
VSS (pin 8)
Circuit common is connected to this pin. This should
be the most negative point in the circuit.
White (pin 3)
This output is identical to the others except that in
many sequences, it is held continuously on. The
intention was that this would control a special group
of LEDs on the top of the tree (for a star or other
ornament).
Ordering Information
These integrated circuits are available in either the 300 mil plastic DIP format, or in the 208 mil SOIC surface
mount type of package. To order, add the appropriate suffix to the part number:
300 mil Plastic DIP............................... ELM711P
208 mil SOIC..................................... ELM711SM
All rights reserved. Copyright 2009 by Elm Electronics Inc.
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.
ELM711DSA
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