Motorola D10 Service Manual page 60

BenQ
Baseband a Voice A/D D/A module. The micro-controller serial port
allow read and write access of all internal registers under the arbitration
of the internal bus controller.
3.2.7 SIM card shifters (SIMS)
To allow the use of both 3V or 5V SIM card types, a SIM level
shifter module is included in NAUSICA which interfaces the SIM signal
(SRST, SIO, SCLK) at a constant 3V level with Ulysse and 3V or 5V
level with the SIM card depending on SIM type. A charge-pump is
used to generate a 3V or 5V supply at pin SVDD from the battery
voltage.
3.2.8 Voltage Regulation (VREG)
Linear regulation is performed by several low dropout (LDO)
regulators to supply analog and digital baseband circuits.
(1) LDO R1 generates the supply voltage (2.5V, 1.8V, 1.4V and 1.2V)
for the digital core of Ulysse. In 56f16, it is programmed to 1.8V.
This regulator takes power from the battery voltage and it has a
backup through BBS system.
(2) LDO R1B generates the supply voltage 2.0V for the digital core
of NAUSICA. It is supplied by the battery.
(3) LDO R2B generates the supply voltage 2.9V for the digital I/O's
of Ulysse and Nausica. It is supplied from battery voltage and
has a backup through BBS system.
(4) LDO R2 generates the supply voltages 2.9V for Ulysse memory
interfaces I/O's. It has a backup through BBS system.
(5) LDO R3 generates the supply voltage 2.9V for the analog
functions of NAUSICA.
The backup battery switch (BBS) generates at its output an
uninterrupted power rail (UPR) of which purpose is to supply
continuously the minimum necessary circuitry of the power-control
functions either from the main battery of from the backup battery
3.2.9 Baseband Serial Port (BSP)
The BSP serial interface is used for both configuration of the GSM
baseband and voice A/D D/A (read and write operation in the internal
registers), and transmission of the radio data to the DSP during
reception of a burst by the downlink part of the GSM baseband & voice
A/D D/A. Four pins are used by the serial port: BFSR and BDR for
19
Rev 1.0