Power Up Sequence - Nokia 6235 Baseband Description And Troubleshooting

Nokia Customer Care

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
Reference signal
PwrOnX
Charger Detection
RTC
UEMRSTX
VCORE
VFlash1
VIO
VANA
VR3
19.2MHz Clk
PURX
Sleep Clock
Issue 1 04/2005
Figure 2).
t1 t2 t3 t4
Figure 2: Power-on sequence and timing
©2005 Nokia Corporation
6235/6235i/6236i (RM-60)
Baseband Description and Troubleshooting
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
t1 = 20ms t3 = 500us
t2 = 200ms t4 = 20ms
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