SimCom SIM900D Hardware Design page 15

44
RTS
CTS 45
DCD 42
RI 11
DTR 43
Debug interface
DBG_TXD 2
DBG_RXD 1
SIM interface
SIM_VDD 9
SIM_DATA 6
SIM_CLK 7
SIM_RST 8
ADC
ADC0 29
Pulse width modulation( PWM )
PWM 47
RF interface
ANT 33
Charging
VCHG 28
TEMP_BAT 27
SIM900D_Hardware Design_V2.02
I Request to send
O Clear to send
O Data carrier detect
O Ring indicator
I Data terminal ready
O
For debugging and upgrading firmware
I
Voltage supply for SIM card. Support
O
1.8V or 3V SIM card
I/O SIM data input/output
O SIM clock
O SIM reset
I Input voltage range: 0V ~ 2.8V
O PWM
I/O Radio antenna connection
I Charger input
I Battery temperature sensor
15
Smart Machine Smart Decision
keep open.
If these pins are unused,
keep open.
All signals of SIM
interface should be
protected against ESD
with a TVS diode array.
If it is unused, keep open.
If these pins are unused,
keep open.
Impendence must be
controlled to 50Ω.
These pins should be
kept open.
If it is unused, keep open.
2012-05-07