SIM340 Hardware Design
Otherwise, the system is power on.
GND
Digital ground
Power on or power off
PIN NAME I/O
DESCRIPTION
DC CHARACTERISTICS
PWRKEY
I
Voltage input for PWRKEY.
PWRKEY should be pulled low to
power on or power off the system.
The user should keep pressing the
key for a moment when power on
or power off the system because the
system need margin time in order
to assert the software.
VILmax=0.2*VBAT
VIHmin=0.6*VBAT
VImax=VBAT
pull up to
VBAT
Audio interfaces
PIN NAME I/O
DESCRIPTION
DC CHARACTERISTICS DC
MIC1P
MIC1N
I
Positive and negative voice-band
input
MIC2P
MIC2N
I
Auxiliary positive and negative
voice-band input
If unused
keep pins
open
SPK1P
SPK1N
O
Positive and negative voice-band
output
SPK2P
SPK2N
O
Auxiliary positive and negative
voice-band output
Audio DC Characteristics
refer to chapter 3.9.4
If unused
keep pins
open
BUZZER
O
Buzzer output
If unused
keep pin open
AGND
Analog ground
Separate
ground
connection for
external audio
circuits.
If unused
keep pin open
General purpose input/output
PIN NAME I/O
DESCRIPTION
DC CHARACTERISTICS
KBC0~KB
C4
O/4mA
Tri-out, If
unused keep
pins open
KBR0~KB
R4
I/4mA
Keypad interface
Pull up to
VEXT, if
unused keep
pins open
DISP_DAT
I/O/4m
LCD display interface
VILmin=0V
VILmax=0.3 *VDD_EXT
VIHmin=0.7*VDD_EXT
VIHmax= 0.3
VOLmin=GND
VOLmax=0.2V
VOHmin= VDD_EXT-0.2
VOHmax= VDD_EXT
If unused
SIM340_HD_V3.09
18.03.2009
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