SIM900D Hardware Design
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
drive the PWRKEY to low
level voltage for a short time
when power on or power off
the system because the
system need margin time in
order to assert the software.
VILmax=1.2V
VIHmin=2.6V
VIHmax=3.3V
VILmin= 0V
It is already
pulled up
Audio interfaces
PIN NAME
I/O DESCRIPTION
DC CHARACTERISTICS
COMMENT
MIC1P
MIC1N
I
Positive and negative voice
band input
Audio DC Characteristics refer to
chapter 3.10
If unused keep
open.
MIC2P
MIC2N
I
Auxiliary positive and
negative voice band input
If unused keep
open.
SPK1P
SPK1N
O
Positive and negative voice
band output
If unused keep
open.
SPK2P
SPK2N
O
Auxiliary positive and
negative voice band output
If unused keep
open.
AGND
Analog ground
Separate ground
connection for
external audio
circuits.
If unused keep
open.
GERNERAL PURPOSE input/output
PIN NAME
I/O DESCRIPTION
DC CHARACTERISTICS
COMMENT
STATUS
O
Indicate status of module 's
working
If unused keep
open
NETLIGHT
O
Indicate status of module's
network
If unused keep
open
DISP_DATA
I/O
DISP _CLK
O
DISP _CS
O
DISP _D/C
O
Display interface
If unused keep
open
GPO1
O
Normal Output Port
If unused keep
open
KBR0
I/O Normal Output/Input Port
VILmax=0.4V
VIHmin=2.4V
VILmin= 0V
VIHmax= 2.95
VOHmin= 2.7V
VOLmax=0.1V
VOHmax= 2.95V
VOLmin= 0V
KBR0 pin can
be configured as
SIM900D_Hardware Design_V1.04
2010.10.09
19
