SimCom SIM900D Hardware Design page 19

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