VDD (pin 1)
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 not required. Refer to the
Electrical Characteristics section for further
Delay (pin 2)
The logic level at this input pin determines the
minimum time between Camera outputs. A high
level sets a nominal delay of 5 seconds while a low
www.DataSheelte4vUe.lcgoimves 1/2 of a second. This delay is provided
to ensure that the camera has time to prepare for
the next picture, before another cycle is allowed.
PW (pin 3)
The digital level at this pin sets the pulse width of
the output at Camera (pin 7). When at a logic low
level, the time will nominally be 1/4 of a second,
while a high level provides 1 second.
PB (pin 4)
This input is to be connected to a momentary action
spst pushbutton switch. Holding the switch closed
for more than 5 seconds will cause the power to
toggle on (if off), or off (if presently on). If the switch
is released after 2 seconds, but before 4 seconds
pass, the mode will toggle between run and test.
Power up is always to the test mode.
While the switch is being pressed, the LED output
will pulse briefly every second, to assist in counting
time. Once a command is acknowledged, a long
LED pulse will be provided so that you know a
change is to occur.
Trigger (pin 5)
A low level at this input initiates one cycle of circuit
operation. The use of a schmitt trigger on the input
means there are no restrictions on the rise or fall
time of the waveform.
If no trigger pulse occurs after 8 minutes in the test
mode or 32 minutes in the run mode, the circuit will
automatically power itself off.
LED (pin 6)
This output is periodically driven to a high level to
show the various states. If in the test mode, LED
will output a double pulse every 4 seconds, while in
the run mode, a single output occurs every 8
seconds. A Camera output will always blank the
LED output, so the LED cannot affect the picture.
Camera (pin 7)
This output is used to control the camera’s shutter.
Usually a transistor provides the actual interface
between the camera and the ELM307 (see the
VSS (pin 8)
Circuit common is connected to this pin. This is the
most negative point in the circuit.
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............................... ELM307P
200 mil SOIC..................................... ELM307SM
All rights reserved. Copyright ©2001 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.
Elm Electronics – Circuits for the Hobbyist
< http://www.elmelectronics.com/ >
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