User Guide

Nokia Customer Care Troubleshooting - Baseband

6015/6015i/6016i/6019i (RH-55), 6012 (RM-20)

Power Up and Reset

Power up and reset are controlled by the UEM ASIC. The baseband can be powered up in

the following ways:

• By the Power button, which means grounding the PWRONX pin of the UEM

• By connecting the charger to the charger input

• By the RTC alarm, when the RTC logic has been programmed to give an alarm

After receiving one of the above signals, the UEM counts a 20ms delay and enters into

reset mode. The watchdog starts up, and if the battery voltage is greater than Vcoff+, a

200ms delay starts to allow references (etc.) to settle. After this delay elapses, the

VFLASH1 regulator is enabled. Then 500us later the VR3, VANA, VIO, and VCORE are

enabled. Finally, the PURX (Power Up Reset) line is held low for 20 ms. This reset (PURX)

is fed to the baseband ASIC UPP. Resets are generated for the MCU and the DSP. During

this reset phase, the UEM forces the VCTCXO regulator on — regardless of the status of

the sleep control input signal — to the UEM.

The FLSRSTx from the ASIC is used to reset the flash during power up and to put the

flash in power down during sleep. All baseband regulators are switched on when the

UEM powers on. The UEM internal watchdogs are running during the UEM reset state,

with the longest watchdog time selected. If the watchdog expires, the UEM returns to

the 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.

Figure 2 represents the UEM start-up sequence from reset to power-on modes.