Mobile continued to normal boot, must meet the following three conditions. First, the power IC is working properly ; Second, the logic circuit is working properly ; Third, the software runs properly. Among them, the first two instructions are hardware is working properly, the third point is the software properly explained . Specific analysis below.

1 Power IC is working properly

( 1 ) Power Engineering C supply is normal. Power Engineering C to work properly , there must be voltage, this voltage is the battery voltage or the general external power supply voltage.

 

 

( 2 ) have switched trigger signal. The current production of mobile phones , both high level trigger , there are low-level trigger , no matter what the trigger , the trigger signal to be applied to the power supply IC, when you press the power button ( power switch ) , the trigger signal should be switched level changes ( i.e., high to low or low to high ) .

( 3 ) Power IC normal . How the general integrated power IC group controlled and non- controlled voltage regulator circuit, a trigger signal when there is power , the power output of industrial C should be regulated voltage output.

( 4 ) there is power to maintain signal ( watchdog signal ) . Power to maintain the signal from the CPU, power supply IC only get a signal in order to maintain the output power constant voltage , otherwise the phone will not continue to boot.

2 logic circuit is working properly

( 1 ) there is a normal power supply. After pressing the power button , the power supply IC output voltage to a stable power supply for the logic circuits , including CPU, chip , font and registers.

( 2 ) there is a normal system clock. CPU clock is the basis for processing data according to the beat , the phone clock circuit two, one is the clock VCO modules, components and crystal oscillator circuit included , when the normal power supply is turned on , self- oscillation , the formation of 13MHz signal output ; another is the frequency integrated circuits and crystals , the IF IC to get power from the internal oscillator for the crystal oscillator , the output amplified by the IF block ; 13MHz clock usually after

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