hardware design v1 00 2

Smart Machine Smart Decision
SIM900R_Hardware Design_V1.00 14 2012-07-20
GPIO1/KBR4 40 GPIO1/keypad row 4
GPIO9/KBC1 50 GPIO9/keypad column 1
GPIO8/KBC2 49 GPIO8/keypad column 2
GPIO7/KBC3 48 GPIO7/keypad column 3
GPIO6/KBC4 47 GPIO6/keypad column 4
GPIO10 51 GPIO10
GPIO11 67 GPIO11
GPIO12 68 GPIO12
Serial port
RXD 10 I Receive data
This pin should be
pulled up to
VDD_EXT externally.
TXD 9 O Transmit data
RTS 8 I Request to send
CTS 7 O Clear to send
DCD 5 O Data carrier detect
RI 4 O Ring indicator
DTR 3 I Data terminal ready
If these pins are unused,
keep open.
Debug interface
DBG_TXD 27 O
DBG_RXD 28 I
For debugging and upgrading firmware
If these pins are unused,
keep open.
SIM interface
SIM_VDD 30 O
Voltage supply for SIM card. Support
1.8V or 3V SIM card
SIM_DATA 31 I/O SIM data input/output
SIM_CLK 32 O SIM clock
SIM_RST 33 O SIM reset
All signals of SIM
interface should be
protected against ESD
with a TVS diode array.
SIM_PRESEN
CE
34 I SIM card detection If it is unused, keep open.
ADC
ADC 25 I Input voltage range: 0V ~ 2.8V If it is unused, keep open.
External reset
NRESET 16 I Reset input(Active low)
Recommend connecting
a 100nF capacitor.
Pulse width modulation( PWM )
PWM1 35 O PWM
PWM2 36 O PWM
If these pins are unused,
keep open.
RF interface
RF_ANT 60 I/O Radio antenna connection
Impendence must be
controlled to 50Ω.
Not connect
NC 2,6 -
These pins should be
kept open.