Isd14b20 – Rainbow Electronics ISD14B20 User Manual
Page 7
ISD14B20
Publication Release Date: October 9, 2007
- 7 -
Revision 0
PAD NAME
I / O
FUNCTION
MIC- I
MIC- : Inverting input of the differential microphone signal. While
FT
is enabled,
MIC- pin is disabled and must be floated.
Rosc I
Oscillator Resistor: Connect an external resistor from this pin to V
SSA
to select the
internal sampling frequency.
V
CCA
I
Analog Power Supply: Power supply for analog circuits.
LED
O
LED output: During recording, this output is Low. Also,
LED
pulses Low
momentarily at the end of playback.
I
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,
,
t
ogether with
&
, setup
various fixed-message configurations.
FMC2
FMC1
FMC3
PLAYE
/
FMC2
I
REC
/
/P
R
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.
/P
R
( When
MODE
is active
):
• When
/P
R
is set to Low, level-hold record operation is selected.
• When
/P
R
is set to High, edge-trigger & toggle on-off playback operation is
selected.
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
&
FMC2
, setup various fixed-
message configurations.
FMC1
XCLK
/
FMC3
FT
I
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.
I Level-hold
input.
Norm /
MODE
• 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
,
FMC2
&
pins as below table.
FMC1
FMC3
FMC3
FMC2
FMC1
# of fixed messages
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
V
CCD
I
Digital Power Supply: Power supply for digital circuits.
Notes:
[1]
: Address bits
,
,
,
,
,
,
&
E3
are used to access the memory location.
S0
S1
S2
S3
E0
E1
E2