Sleepclk (Analog); Flash Programming; Connections To Baseband; Baseband Power Up - Nokia 6255 Description And Troubleshooting

Nokia Customer Care

SleepCLK (Analog)

When the system enters sleep mode or power-off mode, the external 32KHz crystal
provides a reference to the UEME. The RTC circuit also uses this clock to turn on the
mobile terminal during power-off or sleep mode.

Flash Programming

Connections to Baseband

The flash programming equipment is connected to the baseband using test pads for
galvanic connection. The test pads are allocated in such a way that they can be accessed
when the mobile terminal is already assembled. The flash programming interface
includes the VPP, FBUSTX, FBUSRX, MBUS, and BSI signals, which are used by the FLS-8
for flashing. The connection is through the UEME, which means that the logic voltage
levels of these signals correspond to 2.78V. Power is supplied to the mobile terminal
using the battery contacts.

Baseband Power Up

The baseband power is controlled by the flash prommer in production and in
re-programming situations. The baseband powers up by applying supply voltage to the
battery terminals. After the baseband is powered up, flash programming indication
begins (see the following "Flash Programming Indication" section).
Issue 2 05/2005
Figure 9: 32KHz analog waveform at 32KHz crystal input
©2005 Nokia Corporation
6255/6255i6256/6256i (RM-19)
Baseband Description and Troubleshooting
Company Confidential Page 19