i.MX 258 Stop mode

cancel
Showing results for 
Show  only  | Search instead for 
Did you mean: 

i.MX 258 Stop mode

1,540 Views
yslin
Contributor I

How do to set to let iMX258 into Stop mode ?

I have try to set Clock Control register(CCTL) and LP CTL fleid to 11 and then  measured the current consumption .

It have been reduced to 25mA. (I have removed other peripheral ICs.)

is it right ?

Labels (1)
0 Kudos
11 Replies

1,258 Views
VladanJovanovic
NXP Employee
NXP Employee

(*( unsigned long *) CCM_CCTL ) |= 0x03000000 ;  // Stop mode

asm ("MCR p15, 0, r1, c7, c0, 4 \n\t" ) ;   // WFI

Above should be fine. Make sure JTAG is not connected as it may prevent going to low power mode.

1,258 Views
yslin
Contributor I

" JTAG is not connected as it may prevent going to low power mode." means I need to remove those pull-up and pull-down resistors, is it right ?


Snap1.jpg

0 Kudos

1,258 Views
VladanJovanovic
NXP Employee
NXP Employee

No, it means that you shouldn't have JTAG probe connected and initialized for debug of i.MX25.

For reducing power consumption, make sure modules that are not used are disabled and clocks to it gated. Memory needs to be put so self-refresh mode as well.

1,258 Views
yslin
Contributor I

Thanks a lot.

I still do reducing current consumption to under 6mA for stop mode, but I can't achieve until I remove 3.3V power .

Can 3.3V power be removed under stop mode ?

0 Kudos

1,258 Views
VladanJovanovic
NXP Employee
NXP Employee

No, I don't think it's good to remove those voltages. What is the value of OSC24M_DOWN in PMCR2? Please also check detailed description of entering STOP mode in Chapter 15.4.3.2.4 of i.MX25 ref. manual.

0 Kudos

1,258 Views
yslin
Contributor I

Thank you ,

But I have a problem .  The PMIC that I used can't change to 1.0V , means is it can't into stop mode ?

or If 3.3V is removed under stop mode , what are side effects ?

0 Kudos

1,258 Views
VladanJovanovic
NXP Employee
NXP Employee

No, it does not mean that. i.MX25 will go to stop mode even if you don’t reduce voltage. Reducing voltage just reduces even further leakage current in STOP mode.

Datasheet specifies what are the required voltages and whether it’s possible to disable them. Device behavior is not guaranteed if datasheet is not followed. I don’t think datasheet mentions you can remove those voltages.

0 Kudos

1,258 Views
yslin
Contributor I

Thank you very much.

If core voltage doesn't reduce to 1.0V , Have a idea for the leakage current that core voltage is 1.45V in stop mode  ?

0 Kudos

1,258 Views
VladanJovanovic
NXP Employee
NXP Employee

Sorry, I don’t have such information.

0 Kudos

1,258 Views
yslin
Contributor I

If only imx258 is on the board and let it into Stop mode , What is the current consumption , less than 30mA or ..... ?

0 Kudos

1,258 Views
VladanJovanovic
NXP Employee
NXP Employee

Datasheet shows guaranteed minimal values possible to achieve over the temperature range supported for i.MX25. But real number will also depend on the system, how much current is leaked through GPIOs etc. So if you see higher current on certain power rail, please check how it’s GPIOs are configured and what might be causing higher consumption on that domain.

Vladan

0 Kudos