NHL-10
Baseband Troubleshooting
CCS Technical Documentation
ISSUE 2 01/2004
COMPANY CONFIDENTIAL
11
Copyright © 2003 Nokia. All Rights Reserved.
Figure 7: CBUS waveform
If you are able to get the phone to boot up and can reach Phoenix BB self tests it is possible to
test the functionality of each component attached to Cbus. Use:
• ST_UEM_CBUS_IF_TEST to test UEM Cbus interface
• ST_LPRF_IF_TEST to test Bluetooth Cbus interface
• ST_ZOCUS_CBUS_IF_TEST to test Zocus Cbus interface
If an error is found testing any of the above components you should replace or re-solder the
failing component.
FBUS
FBUS is a two wire RX and TX interface between UPP and flash/test interface. The bus goes
through UEM, which adjusts the voltage levels to suit UPP_WD2. The interface voltage level
on the phone flash/test pad pattern is 2.78V and on the UPP WD2 end it is 1.8V.
The functionality of this interface should not affect the device boot into NORMAL, LOCAL nor
TEST modes. Phoenix tests can be performed through the MBUS interface in case of a failure
in FBUS interface. Flashing is not possible if there is a problem in FBUS interface.
MBUS
MBUS is a two-wire RX and TX interface between UPP and UEM. From UEM the interface con-
tinues to flash/test interface as a one-wire interface. UEM adjusts the voltage levels.
