User Guide

Figure 28 Old (left) and new (right) charger plugs

Charging is controlled by energy management, and external components are needed to protect the baseband

module against EMC, reverse polarity and transient frequency deviation.

Interfaces

SIM

The SIM interface is the electrical interface between the SIM card and the mobile phone engine.

The data communication between the SIM card and the phone is asynchronous half duplex.

Figure 29 SIM interface connections

SIM Logic level shifting

The SIM interface can support 3V and 1.8V SIM cards.

SIM Power up/down

The SIM power up/down sequence is generated in Retu. This means that Retu generates the reset switch

(RST) signal to the SIM. In addition, the SIMCardDet signal is connected to Retu.

The SIM interface is powered up when the SIMCardDet signal indicates “card in”.

RM-274

System module

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