Rs Mmc Interface - Nokia 6680 RM-36 Service Manual

RM-36
System Module Nokia Customer Care
Figure 105 SIM interface
Retu handles SIM card detection and the detection method is based on the BSI line. Due to location of the SIM
card removal of the battery causes quick power down of the SIM IF. The Retu SIM1 interface supports both the
1.8V and 3.0V SIM cards. SIM interface voltage is first 1.8V when the SIM card is inserted and if the card does not
response to the ATR (Answer To Reset) 3V interface voltage is used. The data communication between the card
and the phone is asynchronous half duplex and the clock supplied to cards is 1-5MHz, which is 3.2MHz by default
(in GSM system). The data baud rate is SIM card clock frequency divided by 372 (by default), 64, 32 or 16.

RS MMC interface

The reduced size (24mm x 18mm x 1.4mm) multimedia card slot is located under the battery. The device
supports RS MMC hot insertion so it is possible to remove/insert the card when the phone is powered on.
RS MMC card is connected to the Helen3 processor MMC/SDIO2 (1.8V) interface. MMC interface is shown in the
following figure:
Figure 106 MMC interface
The basic multimedia card concept is based on the following communication signals CLK, CMD and DAT. With
each cycle of the CLK signal one bit transfer on the DAT and CMD line is done. The maximum CLK frequency is
20MHz (specified in multimedia card specification). Maximum used CLK frequency at the time is 16MHz. CMD is
a bi-directional command channel used for card initialization and data transfer commands. CMD signal has two
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