User Guide

PAMS Technical Documentation 3. System Module
NSD-5
Issue 1 05/02 Nokia Corporation Page 31
Power Up by Power Button
t
1
< 1 ms
t
2
11 - 6 ms, VCXO settled
t
3
: 62 ms, PURX delay generated by CCONT
(*)VR1 VR6 and Vref might be later than VBB
Figure 15: Timing of power-up sequence by power button
After PWR–key has been pushed, CCONT sends PURX reset to MAD4 and turns on VR1,
VBB, and VR6 regulators (if battery voltage has exceeded 3.0 V). VR1 supplies VCTCXO,
VBB supplies MAD, and VR6 supplies CAFE. After the initial delay, t
2
, VCTCXO starts to
give a proper 19.2MHz clock to CAFE, which further divides it to 9.83MHz for MAD4.
CAFE will output the 9.83MHz clock only after the PURX reset has been removed. After
delay, t
3
, CCONT releases PURX and MAD4 can take control of the operation of the
phone.
After MAD4s reset is released, MCU–SW detects that the PWR–key is still pushed and
shows the user that the phone is powering up by turning on the LCD and the lights.
MCU–SW then powers up the RF receiver part. See Figure 16 for timing information.