Power Up Sequence - Nokia 3155i Troubleshooting Manual

3155/3155i (RM-41), 3152 (RM-61)
Baseband Description and Troubleshooting

Power Up Sequence

When the mobile terminal is dead or jammed always check the Power Up Sequence of
the baseband area. Verify all regulator and reset signals are correct to ensure proper
power up of UEMEK and D2800 (see
Reference signal
PwrOnX
Charger Detection
RTC
UEMRSTX
VCORE
VFlash1
VIO
VANA
VR3
19.2MHz Clk
PURX
Sleep Clock
Page 6
t1 t2 t3 t4
Figure 1: Power-on sequence and timing
©2005 Nokia Corporation
Figure 1).
Reset mode is entered and the watchdog
starts. VCORE enabled, providing power to
D2800.
End of settling time (only if Vbat > Vcoff+_);
VFLASH1 regulator enabled
VR3, VANA, VIO enabled; PURX held
LOW
D2800 processor, MCU, and DSP are
reset; VCTCXO regulator forced on
t1 = 20ms t3 = 500us
t2 = 200ms t4 = 20ms
Company Confidential ISSUE 1 07/2005