AnsweredAssumed Answered

About LPSTOP3 mode and VREG_CTRL

Question asked by Soichi Yamamoto on Apr 25, 2014
Latest reply on Apr 30, 2014 by Naoum Gitnik

Hi,

 

I want to reduce current consumption in a standby mode(LPSTOP3 mode).

Therefore I set FIRC OFF out of LPSTOP3.

 

case 1:

I tested follows. And system reset occurred when I returned from LPSTOP3.

 VREG_CTRL=0x01

 FIRC、FOSC、SOSC=OFF。

 SIRC=ON。

 CCM_CCSR[SYS_CLK_SEL]=0x01

 A mode changes to LPSTOP3.

 

case 2:

I tested follows. And I succeed in return from LPSTOP3.

VREG_CTRL=0x03.

FIRC、FOSC、SOSC=off.

SIRC=on.

CCM_CCSR[SYS_CLK_SEL]=0x01.

A mode changes to LPSTOP3.

 

I ask about this problem.

The difference between ”case1” and ”case2”is "VREG_CTRL = 0x01" and" VREG_CTRL = 0x03".

From a reference manual, the first bit of VREG_CTRL is Reserved bit.

From the test mentioned above, I think like a bit with a special function.

Q1)Please tell me about a special function of this bit in detail.

 

Q2)Please tell me the function when I made this bit clear.

 

Q3)Please tell me the function when I made this bit set.

 

Best Regards,

soichi

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