User guide

APR6008
Voice Recording & Playback Device Page 15
Revision 2.1
Sample Application
Figure 15 shows a sample application utilizing a generic
microcontroller and SPI interface for messa
ge management.
The microcontroller uses three
general purpose inputs for the
pla
y, record and skip buttons. Five general purpose I/O sig-
nals are utilized in the SPI interface. The /RESET and /BUSY
si
gnal are not used in this design.
The output si
gnal must be amplified in order to drive a
speaker. Several vendors suppl
y integrated speaker amplifi-
ers that can be used for this purpose.
A microphone amplifier and AGC are recommended. Both
blocks are optional. Several vendors suppl
y integrated micro-
phone/AGC amplifiers that can be used for this purpose.
Note that the AGC circuit can be simplified by using the SQLCAP signal as a
peak detector signal.
Figure 15Sample Schematic using DIP package
All resistors 2.2 K
/CS
DI
DO
VSSD
NC
NC
NC
ANAOUT-
ANAOUT+
NC
/RESET
VSSA
AUDOUT
SQLCAP
SCLK
VCCD
EXTCLK
/INT
SAC
VSSA
NC
/BUSY
NC
NC
VCCA
ANAIN+
ANAIN-
/SQLOUT
28
27
26
25
24
23
22
21
20
19
18
17
16
15
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Generic
Microcontroller
I/O_4
I/O_5
I/O_7
I/O_8
I/O_6
0.1
µF
100K
Vcc
/IRQ
I/O_3
I/O_2
I/O_1
Play
Record
Skip
Vcc
1.0 uF
Vcc
Speaker
APR6008 DIP
AGC
Block
Speaker
Amplifier
Vcc
Mic
Pre-Amp
Mic
Vcc
2.2K
2.2K