User's Manual

GSM/GPRS Module Series
M35 User Manual
M35_User_Manual Confidential / Released 21 / 85
Network Status Indicator
PIN NAME
PIN NO.
I/O
DESCRIPTION
DC
CHARACTERISTICS
COMMENT
NETLIGHT
13
O
Network status
indication
VOHmin=
0.85×VDD_EXT
VOLmax=
0.15×VDD_EXT
If unused, keep
this pin open.
UART Port
PIN NAME
PIN NO.
I/O
DESCRIPTION
DC
CHARACTERISTICS
COMMENT
DTR
20
I
Data terminal ready
VILmin=0V
VILmax=
0.25×VDD_EXT
VIHmin=
0.75×VDD_EXT
VIHmax=
VDD_EXT+0.2
VOHmin=
0.85×VDD_EXT
VOLmax=
0.15×VDD_EXT
If only use TXD,
RXD and GND to
communicate,
recommended
connecting RTS to
GND via 0R
resistor and
keeping other pins
open.
RXD
21
I
Receive data
TXD
22
O
Transmit data
RTS
24
I
Request to send
CTS
23
O
Clear to send
RI
26
O
Ring indication
DCD
25
O
Data carrier detection
Debug Port
PIN NAME
PIN NO.
I/O
DESCRIPTION
DC
CHARACTERISTICS
COMMENT
DBG_
TXD
15
O
Transmit data
Same as above
If unused, keep
these pins open.
DBG_
RXD
14
I
Receive data
SIM Interfaces
PIN NAME
PIN NO
I/O
DESCRIPTION
DC
CHARACTERISTICS
COMMENT
SIM1_
VDD
27
O
Power supply for SIM1
card
The voltage can be
selected by software
automatically. Either
1.8V or 3V.
All signals of SIM
interfaces should
be protected
against ESD with
a TVS diode array.
Maximum trace
length is 200mm
from the module
SIM1_
CLK
30
O
SIM1 clock
VOLmax=
0.15×SIM1_VDD
VOHmin=
0.85×SIM1_VDD