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RH-44
Troubleshooting — BB
CCS Technical Documentation
Page 10
Nokia Corporation Confidential
Issue 1 04/2003
watchdog expires, the UEM returns to power off state. The UEM watchdogs are internally
acknowledged at the rising edge of the PURX signal in order to always give the same
watchdog response time to the MCU.
The following timing diagram represents UEM start-up sequence from reset to power-on
mode.
Figure 5: Power on sequence and timing
Reference signal
PwrOnX
Charger Detection
RTC
UEMRSTX
VFlash1
VIO
VCORE
VANA
VR3
19.2MHz Clk
PURX
t1
t2
t4
t3
32kHz XTAL
t1 = 20ms
t2 = 200ms
t3 = 500us
t4 = 20ms