SIM Tech SIMCom SIM900-DS, Hardware Design

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Smart Machine Smart Decision
SIM900-DS_Hardware Design_V1.00
13
2013-01-20
3.2 Pin Description
Table 4: Pin description
Pin name Pin number I/O Description Comment
Power supply
VBAT 55,56,57 I Power supply
VRTC 26 I/O Power supply for RTC
It is recommended to
connect with a battery or
a capacitor (e.g. 4.7uF).
VDD_EXT 15 O 2.8V output power supply If it is unused, keep open.
GND
2,17,18,29,39,
45,46,53,54,
58,59,61,62,
63,64,65
Ground
Power on/down
PWRKEY 1 I
PWRKEY should be pulled low at
least 1 second and then released to
power on/down the module.
Pulled up internally.
Audio interface
MIC1_P 19
MIC1_N 20
I Differential audio input
SPK1_P 21
SPK1_N 22
O Differential audio output
SPK2_P 23 Single audio output
MIC2_P 24 Single audio input
If these pins are unused,
keep open.
Status
STATUS 66 O Power on status
NETLIGHT 52 O Network status
If these pins are unused,
keep open.
SPI interface
SSI _CLK 11 O
SSI_DATA 12 I/O
SSI _OUT 13 O
SSI _SEL1 14 O
Display interface
If these pins are unused,
keep open.
I
2
C interface
SDA 37 O I
2
C serial bus data
SCL 38 I/O I
2
C serial bus clock
If these pins are unused,
keep open.
GPIOs
GPO1 68 GPO1
GPIO4 49 GPIO4
GPIO3 50 GPIO3
GPIO2 51
I/O
GPIO2
If these pins are unused,
keep open.