ISD14B20
PAD NAME
MIC-
Rosc
V
CCA
LED
PLAYE
/
FMC2
I/O
I
I
I
O
I
FUNCTION
MIC- :
Inverting input of the differential microphone signal. While
FT
is enabled,
MIC- pin is disabled and must be floated.
Oscillator Resistor:
Connect an external resistor from this pin to V
SSA
to select the
internal sampling frequency.
Analog Power Supply:
Power supply for analog circuits.
LED output:
During recording, this output is Low. Also,
LED
pulses Low
momentarily at the end of playback.
PLAYE
: In
Norm
mode, low active input, edge-trigger playback from start to end
addresses & toggle on-off. Debounce & internal pull-up existed.
FMC2
: When
MODE
is active,
FMC2
,
t
ogether with
FMC1
&
FMC3
,
setup
various fixed-message configurations.
REC
/
R/P
I
REC
: In
Norm
mode, level-hold (after 1 sec holding) or edge-trigger (toggle on-off),
low active, recording from start to end addresses. Debounce & internal pull-up
existed.
R/P
( When
MODE
is active
):
•
When
R/P
is set to Low, level-hold record operation is selected.
•
When
R/P
is set to High, edge-trigger & toggle on-off playback operation is
selected.
XCLK
/
FMC3
I
FT
I
Norm
/
MODE
I
V
CCD
I
External Clock:
In
Norm
mode, low active and level-hold input. As
XCLK
activated, Rosc pin accepts external clock input signal, provided resistor at Rosc
must be removed. Connecting this pin to High enables device running on internal
clock via Rosc resistor. If not used,
XCLK
must be at high level.
When
MODE
is active,
FMC3
,
t
ogether with
FMC1
&
FMC2
,
setup various fixed-
message configurations.
Feed-Through
: Low active input, Level-hold, debounce & Internal pull-up required.
When
FT
is selected, the MIC+ input is configured to a single-ended input with
1Vp-p maximum input amplitude and feed-through to the speaker outputs.
Level-hold input.
•
Norm
: When set to High, the device operates under Address trigger condition.
•
MODE
: When set to Low, the device operates under direct trigger condition. The
device reconfigures its pin definitions to fit various fixed-message configurations
utilizing
FMC1
,
FMC2
&
FMC3
pins as below table.
FMC3
# of fixed messages
FMC2
FMC1
0
0
0
1
0
0
1
2
0
1
0
3
0
1
1
4
1
0
0
5
1
0
1
6
1
1
0
7
1
1
1
8
Digital Power Supply:
Power supply for digital circuits.
Notes:
[1]
: Address bits
S0
,
S1
,
S2
,
S3
,
E0
,
E1
,
E2
&
E3
are used to access the memory location.
-7-
Publication Release Date: October 9, 2007
Revision 0
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