hardware design v1 00 2

Smart Machine Smart Decision
SIM900R_Hardware Design_V1.00 13 2012-07-20
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
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 interfaces
MIC_P 19
MIC_N 20
I Differential audio input
SPK_P 21
SPK_N 22
O Differential audio output
LINEIN_R 23
LINEIN_L 24
I Line-in 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.
LCD interface
DISP _CLK 11 O
DISP_DATA 12 I/O
DISP _D/C 13 O
DISP _CS 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.
Keypad interface / GPIOs
GPIO5/KBR0 44 GPIO5/keypad row 0
GPIO4/KBR1 43 GPIO4/keypad row 1
GPIO3/KBR2 42 GPIO3/keypad row 2
GPIO2/KBR3 41
I/O
GPIO2/keypad row 3
If these pins are unused,
keep open.