User Guide

RH-48

Troubleshooting — BB CCS Technical Documentation

SleepCLK (Analog)

However, when the system enters sleep mode or power off mode, the external 32KHz

crystal provides a reference to the UEM RTC circuit to turn on the phone during power

off or sleep mode. (Figure 10.)

Figure 10: 32kHz analog waveform at 32KHz crystal input

Flash programming

Connections to Baseband

The Flash programming equipment is connected to the baseband using test pads for gal-

vanic connection. The test pads are allocated in such a way that they can be accessed

when the phone is assembled. The flash programming interface uses the VPP, FBUSTX,

FBUSRX, MBUS, and BSI connections for the connection to the baseband. The connection

is through the UEM, which means that the logic levels are corresponding to 2.7V. Power

is supplied using the battery contacts.

Baseband Power Up

The baseband power is controlled by the flash prommer in production and in re-pro-

gramming situations. Applying supply voltage to the battery terminals the baseband will

power up. Once the baseband is powered, flash-programming indication is done as

described in the following section.

Flash Programming Indication

Flash programming is indicated to the UPP using MBUSRX signal between UPP and UEM.

The MBUS signal from the baseband to the flash prommer is used as clock for the syn-

chronous communication. The flash prommer keeps the MBUS line low during UPP boot

to indicate that the flash prommer is connected. If the UPP MBUSRX signal is low on

UPP, the MCU enters flash programming mode. In order to avoid accidental entry to the