User Guide

Nokia Customer Care Baseband Description and Troubleshooting
6235/6235i/6236i (RM-60)
Issue 1 04/2005 ©2005 Nokia Corporation Company Confidential Page 7
Power Up Sequence
When phone 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 Figure 2).
Figure 2: Power-on sequence and timing
Reference signal
PwrOnX
Charger Detection
RTC
UEMRSTX
VCORE
VFlash1
VIO
VANA
VR3
19.2MHz Clk
PURX
t1 t2 t4t3
Sleep Clock
t1 = 20ms
t2 = 200ms
t3 = 500us
t4 = 20ms
Reset mode is entered and
the watchdog starts
End of settling time (only if Vbat > Vcoff+_);
VFLASH1 regulator enabled
VR3, VANA, VIO, and VCORE enabled;
PURX held LOW
D2800 processor, MCU, and DSP are
reset; VCTCXO regulator forced on