I1800 SERIES
8. RECLEDoperation
The RECLED output pin provides an active-LOW signal, which can be used to drive an LED as a
“record-in-progress” indicator. It returns to a HIGH state when the REC pin is released LOW or when
the recording is completed due to the memory being filled. This pin also pulses LOW to indicate the
end of a message has been reached.
9. ROSC operation
The duration of the device can be varied by changing the value of R2 (ROSC). This means the I1800
device can actually be between 6 to 16 seconds duration. See the curve below, which charts typical
durations when the ROSC is varied from 80 Kꢀ to 160 Kꢀ.
This feature allows frequency shifting where a recorded voice or sound can be played back faster or
slower than normal for special effects. For example, use a 100 Kꢀ resistor to make the recording and
then playback with either an 80 Kꢀ resistor for faster “chipmunk” talk or with a 120 Kꢀ resistor for a
slower, lower voice.
Another feature is a “Pause” or interrupt function that can be done by taking the ROSC resistor to VCC to
stop playback momentarily, resuming when the resistor is connected back to ground.
Chart 1: ISD Duration Versus ROSC at TA = 25°C and VCC = 3.0V
80
100
120
140
)
160
Typical ROSC (K
Ω
Publication Release Date: May 2003
Revision 0.0
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