Manual

ISD18B12
- 8 -
T
Deb
PlayL
LEDP
SP+
SP-
LEDR
T
D2
T
r
T
D2
5.5. Sound Effect (
SE ) Operation :
• Beeping feature for recording. Once active, one-beep indicates the start of recording and two-beep
represents the end of recording.
5.6. Microphone amplifier gain
• Two external resistors, R
I
and R
O
, are used to adjust the microphone amplifier gain with respect to the
incoming signal.
5.7. Playback (supersedes Record) Operation :
• Playback takes precedence over the Recording operation.
• If either PLAYE or PLAYL is activated during a recording cycle, the recording immediately ceases and
playback of the just-recorded message performs accordingly.
5.8. Feed-Through mode Operation :
• As
FT is held Low, the input signal from MICIN will directly transmit to the speaker outputs.
• If either
RECE is triggered or RECL is held Low simultaneously after FT is enabled, then input signal
will be recorded into memory while the Feed-Through mode is still on.
• After
FT is enabled, activating either PLAYE or PLAYL will first disable the feed-through path and
play the recorded message. Once playback is completed, the feed-through feature resumes.
5.9.
LEDR Operation :
•
LEDR stays on during recording.
• Also,
LEDR pulses Low momentarily at the end of playback operation.
5.10.
LEDP Operation :
•
LEDP stays on during playback.
• Also,
LEDP pulses Low momentarily at the end of recording.
5.11. Rosc Operation :
• When the R
OSC
varies from 80 KΩ to 160 KΩ, the duration changes from 6 to 12 seconds accordingly.
• When R
OSC
resistor value is changed during playback, the tone of a recorded message will alter either
faster or slower.
5.12. Speaker Outputs
• Both SP+ and SP- outputs can be used to drive an 8Ω speaker differentially. They are tri-state while
device is in power down status.