Rs Mmc Interface - Nokia RM-42 Service Manual

RM-42
Nokia Customer Care System Module

RS MMC interface

The device has one slot for reduced size (24mm x 18mm x 1.4mm multimedia card. The device supports RS MMC
hot insertion so it is possible to remove/insert the card when the phone is powered on.
Figure 103 Reduced size MMC
RS MMC card is connected to the Helen3 processor MMC/SDIO2 (1.8V) interface. MMC interface is shown in the
following figure:
Figure 104 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
operational modes open-drain and push-pull mode. Open-drain mode is used for card initialization and push-
pull mode for fast command transfer. CMD commands are sent by the host and CMD responses are sent by the
card. DAT is a bi-directional data channel, which operates at push-pull mode.
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