> 3.9 | SIM Interface

> The baseband processor has an integrated SIM interface compatible with the ISO 7816 IC Card standard. This is wired to the host interface (board-to-board connector) in order to be connected to an external SIM card holder. Six pins on the board-to-board connector are reserved for the SIM interface.
> The SIM interface supports 3V and 1.8V SIM cards. Please refer to Table 30 for electrical specifications of the SIM interface lines depending on whether a 3V or 1.8V SIM card is used.
> The CCIN pin serves to detect whether a tray (with SIM card) is present in the card holder. Using the CCIN pin is mandatory for compliance with the GSM 11.11 recommendation if the mechanical design of the host application allows the user to remove the SIM card during operation. To take advantage of this feature, an appropriate SIM card detect switch is required on the card holder. For example, this is true for the model supplied by Molex, which has been tested to operate with TC65 and is part of the Siemens reference equipment submitted for type approval. See Chapter 8 for Molex ordering numbers.

> Table 14: | Signals of the SIM interface (board-to-board connector)

> Signal | Description
> CCGND | Separate ground connection for SIM card to improve EMC. Be sure to use this ground line for the SIM interface rather than any other ground pin or plane on the module. A design example for grounding the SIM interface is shown in Figure 51.
> CCCLK | Chipcard clock, various clock rates can be set in the baseband processor.
> CCVCC | SIM supply voltage.
> CCIO | Serial data line, input and output.
> CCRST | Chipcard reset, provided by baseband processor.
> CCIN | Input on the baseband processor for detecting a SIM card tray in the holder. If the SIM is removed during operation the SIM interface is shut down immediately to prevent destruction of the SIM. The CCIN pin is active low. The CCIN pin is mandatory for applications that allow the user to remove the SIM card during operation. The CCIN pin is solely intended for use with a SIM card. It must not be used for any other purposes. Failure to comply with this requirement may invalidate the type approval of TC65.

> The total cable length between the board-to-board connector pins on TC65 and the pins of the external SIM card holder must not exceed 100mm in order to meet the specifications of 3GPP TS 51.010-1 and to satisfy the requirements of EMC compliance.
> To avoid possible cross-talk from the CCCLK signal to the CCIO signal be careful that both lines are not placed closely next to each other. A useful approach is using the CCGND line to shield the CCIO line from the CCCLK line.
> Note: No guarantee can be given, nor any liability accepted, if loss of data is encountered after removing the SIM card during operation. Also, no guarantee can be given for properly initializ ing any SIM card that the user inserts after having removed a SIM card during operation. In this case, the application must restart TC65.