Huawei Y511-U030 Repair Manual page 38

XXXX The basic version Repair Manual
Here to press the power button as an example to illustrate the boot process:
Press the power button, the KEYON input is high, the PMU according to the state power on the
boot process. Starting at power on In the process, as long as the power button is released, the
KEYON signal is low, power on the boot process terminate.
1) For the RTC powered LDO always open. After the start button pressed about 100ms,
PMU internal reference open;
2) 13ms reference, open the PMU internal battery voltage comparator, judge the battery
voltage is greater than the starting voltage of about 310us;
3) If the battery voltage is greater than the starting voltage, LDOD1, DCDC1, DCDC2,
DCDC4, DCDC3, LDOA8/9/10, and USB powered LDOD6 in turn power supply, DCDC
interval of about 213us, LDO interval of about 61us. Whether the eMMC powered
LDOD7 opening is controlled by the LDOD7EN pin;
4) PMU sends the RSTOUTB signal, the DBB reset, reset signal from the LDOD1 opened at
least 100ms calculation;
5) After the reduction, OSCEN high, LDOA1/2/3/4/5 is opened by the corresponding
LDOxEN external pin control. Application, 26M crystal powered LDO corresponding to
the LDOxEN connected to the OSCEN;
6) PWREN high, successful start-up;
The shutdown is divided into normal and abnormal shutdown shutdown.
Normal shutdown refers to the PWREN caused by the shutdown, when the baseband
processor receives the shutdown trigger conditions, control chip into the off stage. In the off stage,
application to perform some save operation, control the PWREN pin is low. PMU to PWREN
signal detection becomes lower than 20ms, which entered the shutdown period.
2013-09-25
V1.0
华为机密，未经许可不得扩散
internal public
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