SIM340 Hardware Design
Both 1.8V and 3.0V SIM Cards are supported.
The SIM interface is powered from an internal regulator in the module having normal voltage 3V.
All pins reset as outputs driving low. Logic levels are as described in table
Table
15
: Pin definition of the SIM interface
Name
Pin
Function
SIM_VDD
19
SIM Card Power output automatic output on SIM mode
，
one is 3.0V±10%, another is 1.8V±10%. Current is about
10mA.
SIM_DATA
21
SIM Card data I/O
SIM_CLK
23
SIM Card Clock
SIM_RST
25
SIM Card Reset
SIM_PRESENCE
16
SIM Card Presence
Following is the reference circuit about SIM interface. We recommend an Electro-Static discharge
device ST (
) ESDA6V1W5 or ON SEMI (
ANTI”. The 22
Ω
resistors showed in the following figure should be added in series on the IO line
between the module and the SIM card for protecting the SIM I/O port. The pull up resistor (about
10K
Ω
) must be added on the SIM_DATA line. Note that the SIM peripheral circuit should be
closed to the SIM card socket.
The SIM_PRESENCE pin is used for detecting the SIM card removal. You can use the AT
command “AT+CSDT” to set the SIMCARD configuration. For detail of this AT command,
please refer to
document [1]
:
You can select the 8 pins SIM card holder. The reference circuit about 8 pins SIM card holder
illustrates as following figure.
SIM340_HD_V3.09
18.03.2009
44
