Sony Ericsson C702 Troubleshooting Manual page 88

Resistance Identification and Temperature Measurement
The resistance identification mode utilizes the constant current source to feed the battery
data output while monitoring the voltage at the battery data node with general purpose
ADC. The conversion is started through I2C.
Resistance Identification (A) and Temperature Measurement (B)
SIM Interface
The SIM interface supplies level shifting between the digital baseband controller and the
SIM/USIM card. Moreover, hard-wired SIM deactivation functionality manages removal of
a SIM card that has not been powered down.
Block Diagram of the SIM Interface:
FUNCTIONAL OVERVIEW Technical Description
CODEC Overview
The CODEC is encoding analog audio signals and analog voice signals into digital signals
using ADCs. This is done in the coder section of the CODEC, also named the TX path
(transfer section). The CODEC is also decoding digital audio signals and digital voice
signals into analog signals using DACs. This is done in the decoder section of the
CODEC, also named the RX path (receiver section).
CODEC Block Schematic:
CODEC CCO Voltage Source
There is an internal voltage source CCO that provides the necessary drive current for
electret microphones. The voltage source is I²C programmable to 2.2 V or 2.4 V. The
source can be disabled during standby. A typical use case with a microphone connected
to MIC1 and the CCO is shown in picture below.
SEMC Troubleshooting Manual
C702
1221-7857 rev. 1 88 (115)