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iMX6Q-SD CPU can't wake up from deep sleep in LDO internal bypass mode

Question asked by Miles Wang on Aug 31, 2015
Latest reply on Oct 14, 2015 by Yuri Muhin

Hello

 

We encountered a CPU hang issue when wake up from deep sleep mode.  We're using iMX6Q-SD board.

 

Case-1: Before and after deep sleep mode, below configuration works fine.

-  CPU=996MHz, PMIC-ARMCORE(SW1A/B)=1.275V

-  PMU_REG_CORE-REG0_TARG(4–0)= 10110 (1.250V:LDO Enable )

 

Case-2: Before and after deep sleep mode, below configuration has <10% hang ratio (Can't wake up).

-  CPU=996MHz, PMIC-ARMCORE(SW1A/B)=1.275V

-  PMU_REG_CORE-REG0_TARG(4–0)= 11111 (LDO internal bypass )

 

Case-3: 100% can't wake up after step 3.2

3.1  When normal works:

CPU=996MHz, PMIC-ARMCORE(SW1A/B)=1.275V

PMU_REG_CORE-REG0_TARG(4–0)= 11111 (LDO internal bypass )

 

3.2 Just before deep sleep,

CPU=996MHz, PMIC-ARMCORE(SW1A/B)=1.275V

-  PMU_REG_CORE-REG0_TARG(4–0)= 11110 (LDO analog bypass for ERR005852 ) or 10110 (1.250V:LDO Enable )

 

3.3 After deelp sleep,

-  CPU=996MHz, PMIC-ARMCORE(SW1A/B)=1.275V

-  PMU_REG_CORE-REG0_TARG(4–0)= 11111 (LDO internal bypass )

 

From our testing, it seems that only LDO enable mode can stably work .

Can you give us some suggestions how to make LDO internal bypass mode stably work ?

 

Thanks, Miles

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