SIM Tech SimCom SIM340 Hardware Design page 44

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
SIM_VDD 19
SIM_DATA 21
SIM_CLK 23
SIM_RST 25
SIM_PRESENCE 16
Following is the reference circuit about SIM interface. We recommend an Electro-Static discharge
device ST (www.st.com ) ESDA6V1W5 or ON SEMI
ANTI". The 22Ω 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
10KΩ) 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
Function
SIM Card Power output automatic output on SIM mode，
one is 3.0V±10%, another is 1.8V±10%. Current is about
10mA.
SIM Card data I/O
SIM Card Clock
SIM Card Reset
SIM Card Presence
(www.onsemi.com
44
) SMF05C for "ESD
18.03.2009