Clocking Scheme - Nokia 9000i Service Manual

RAE/RAK–1N
Baseband

Clocking scheme

DSP Clock
60.2 MHz
differential sine
wave
OSCILLATOR
AUDIO
CODEC
DSP
Codec Sync Clock
Codec Main Clock
8 kHz
and data Transfer
clock
512kHz
DBUSCLK 512kHz
DBUSSYNC 8kHz
Most of the clocks are generated from the 26 MHz VCXO frequency by
the ASIC:
– 26 MHz clock for the MCU . SCL divides this by two and supplies a
13 MHz clock to the MCU.
– 13 MHz for the RFI. The ASIC also generates 135.4 kHz sleep mode
clock for the RFI.
– 3.25 MHz clock for SIM . When there is no data transfer between the
SIM card and the baseband the clock can be reduced to 1.625 MHz.
Some SIM cards also allows the clock to be stopped in that mode.
– 512 kHz main clock for the codec and for the data transfer between
the DSP and the codec.
– 8 kHz synchronisation clock for data transfer between the DSP and
the codec.
– 512 kHz clock and 8 kHz sync. clock for the DBUS data transfer
Page 2–18
RFI Clock 13 MHz
Sleep Mode:
135.4kHz
enable
Figure 3. Clocking Scheme
Technical Documentation
RF System Clock
26 MHz
RFI
VCXO
ASIC
3.25 / 1.625
MCU Clock
26 MHz
SCL
MCU Clock
13 MHz
MCU
Original, 08/96
After Sales
SIMCLK
MHz