Nokia 6020b Service Manual

Issue 1 03/2005

COMPANY CONFIDENTIAL

RM-31
7 - System Module

Nokia Customer Care

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Block diagram

Figure 1:Baseband block diagram

UEMEK supplies both baseband and RF with power via built in voltage regulators, which are
connected to the battery. The RF parts use mainly 2.78 V and the baseband parts 1.8V I/O volt-
age. The UPP core is supplied with programmable core voltage of 1.0V, 1.3V or 1.5V. UEMEK
includes 7

linear LDO (Low Drop-Out) regulators for baseband and 7 regulators for RF. It also

includes 4 current sources for biasing purposes and internal usage. The UEMEK is furthermore
supplying the SIM interface with a programmable voltage of 1.8V or 3V.

Note: 5V SIM cards are no longer supported by DCT-4 generation Baseband.

UPP operates from a 26 MHz clock coming from the RF ASIC Helgo. The clock signal is divided
by two down to the nominal system clock frequency of 13 MHz. The DSP and MCU contain
PLLs, which can multiply the system clock to a higher frequency.

A real time clock function is integrated into the UEMEK, which utilizes the same 32kHz clock
supply as the sleep clock.

The communication between UEMEK and UPP is implemented using two bi-directional serial
busses, CBUS and DBUS. The CBUS is controlled by the MCU and operates at a speed of 1
MHz. The DBUS is controlled by the MCU and operates at a speed of 13 MHz. Both processors
are located in the UPP.