topic Re: Problems putting KL03 into VLPS and reducing power consumption in Kinetis Microcontrollers

Problems putting KL03 into VLPS and reducing power consumption

willx — Fri, 27 Mar 2015 17:41:03 GMT

Hi all,

1. What I'm trying to do:

a- Put KL03 into VLPS mode

b- Switch from using the 48MHz HIRC to the 2MHz LIRC2M

c- Reduce power consumption from a few mA's to something lower than 100uA

d- Go from VLPS back to RUN mode on an SPI slave mode receive through AWIC

2. How I'm doing it:

a- Here are the 2 functions I am using to enter and exit VLPS:

void vlps_enter(void)

{

SMC_PMCTRL = SMC_PMCTRL_STOPM(2));

dummyread = SMC_PMCTRL;

(void)dummyread;

SCB_SCR |= SCB_SCR_SLEEPDEEP_MASK;

dsb();

wfi();

isb();

}

void vlps_exit(void)

{

SMC_PMCTRL &= ~SMC_PMCTRL_STOPM_MASK;

SCB_SCR &= ~(SCB_SCR_SLEEPDEEP_MASK | SCB_SCR_SLEEPONEXIT_MASK);

}

b- Here are the 2 functions I use to switch from HIRC to LIRC2M:

void set_HIRC(void)

{

MCG_MC |= MCG_MC_HIRCEN_MASK;

MCG_C1 = MCG_C1_CLKS(0);

MCG_C2 = 0;

while (((MCG_S & MCG_S_CLKST_MASK) >> MCG_S_CLKST_SHIFT) != 0x00);

}

void set_LIRC(void)

{

MCG_MC = 0;

MCG_C1 = MCG_C1_CLKS(1);

MCG_C2 = 0;

while (((MCG_S & MCG_S_CLKST_MASK) >> MCG_S_CLKST_SHIFT) != 0x01);

}

c- At bootup I run this to enable HIRC and enable going into VLPS and VLLS modes:

set_HIRC();

SMC_PMPROT = (SMC_PMPROT_AVLP_MASK | SMC_PMPROT_AVLLS_MASK);

d- When the conditions to enter VLPS are met (KL03 is idle and has no pending tasks), I call the 2 functions like this:

set_LIRC();

vlps_enter();

// KL03 is in VLPS here

vlps_exit();

set_HIRC();

d- My KL03 is configured as an SPI slave (with SPISWAI bit set in SPI0_C2 register) and expect that the KL03 would exit VLPS whenever an SPI transfer is coming its way

3. What I'm seeing:

a- With the code I have above, I measured current consumption at 0.9mA which seems very high to me in VLPS and there's no peripherals running (no ADC, no LPUART... nothing)

b- Another problem is that with this code, the KL03 never properly wakes up and processes the SPI transfer it's receiving.

c- However, if I just remove the set_LIRC() call, power consumption goes to 1.8mA and the SPI transfer works great and I have no issues (other than the high power consumption)

4. My questions:

a- The power numbers I'm seeing are high, is there anything else I need to change to get very low numbers in the 100uA range?

b- Any thoughts on wether the switch to LIRC2M is actually needed?

c- Any idea why if I switch to LIRC2M, the SPI wakeup doesn't work?

Any help is greatly appreciated.

Thanks!

Re: Problems putting KL03 into VLPS and reducing power consumption

jeremyzhou — Mon, 30 Mar 2015 08:21:17 GMT

Hi Will,

The current consumption of the VLPS you measured is much higher than datasheet states.

So I think you need to check whether KL03 enter the VLPS mode correctly or not.

I'd like to suggest that you can refer to the low power demo that SDK develop kit provides and please download it through the link as below.

FRDM-KL03Z|Freedom Development Board Platform|Freescale
Have a great day,
Ping

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Re: Problems putting KL03 into VLPS and reducing power consumption

rickstuart — Mon, 30 Mar 2015 14:52:20 GMT

FYI, I was doing some similar current checks on a LK27 (FRDM-KL27Z Freescale development board). BEWARE!!! You need to do the current checks with out the debugger!!! Here's my thread:

Re: VLPS mode started from debugger draws 2mAs . Even if debugger is turned off. Even after hard reset. Only draws exepcted current (4.9uA) after a power cycle.

As to why the SPI isn't getting you out of VLPS, I thought you needed an interrupt to get out of VLPS. I went down the path of setting bits in VNIC on the '27 for a timer to get out of VLPS.

Re: Problems putting KL03 into VLPS and reducing power consumption

willx — Mon, 30 Mar 2015 21:10:34 GMT

Thanks for your response Jeremy.

I think I am going into VLPS because if I remove the calls to vlps_enter() and vlps_exit(), the current consumption is at 6.6mA. With the calls, the current consumption is at 1.8mA. So I am able to go into a lower power state.

I took a look at the sample code in the SDK you suggested and replaced my code with it and I still see the same power numbers. So there must be something that is left on and consuming more power.

Re: Problems putting KL03 into VLPS and reducing power consumption

willx — Mon, 30 Mar 2015 21:12:25 GMT

Thanks for your reply Rick.

The numbers I quoted are withe debugger detached. Attaching the debugger adds about 0.5mA for me.

And my SPI interrupt is enabled. If I don't change from HIRC to LIRC2M, the SPI IRQ works fine. Only when I switch to the lower clock that the SPI doesn't wake up.

Re: Problems putting KL03 into VLPS and reducing power consumption

rickstuart — Mon, 30 Mar 2015 22:35:06 GMT

WRT the current. So you managed to get the current down to where you expected it?? Note, pressing the red "X" on the debugger tool was not enough for me. Neither was pressing reset on the development board. I needed to cycle the power to the processor to get really low currents.

I'm not sure about the interrupt. If the interrupt really works when you stay out of VLPS - I think it should work when you are in VLPS. Check to make sure you clear the interrupt flag before getting out of the interrupt routine. But you would have had to do that even if you never entered VLPS. Humm. Have to think about this one. FYI, since I can't use the debugger to tell me where my code is executing, I started using the LEDs on the Freescale development boards to indicate I was in main() or one of my interrupts.

Re: Problems putting KL03 into VLPS and reducing power consumption

willx — Mon, 30 Mar 2015 23:34:18 GMT

No, I'm still having problems getting the current to the low level I expect it to be at.

I'm assuming that to get to the lowest possible power consumption I need to do the following: go into VLPS AND switch from the HIRC 48MHz clock to the LIRC 2MHz clock.

At the moment, I have 2 problems:

1. When I try to do both of these things, my application doesn't work because of the SPI transfer not waking it up.

2. Going into VLPS and not changing the clock used is consuming 1.8mA now which is still high. If I change the clock, it drops even more to 0.9mA but I would expect it to be much lower.

The code I'm using is in my original post and it matches the SDK code that Jeremy pointed me too and other sample codes I found in the community.

Any help or guidance would be greatly appreciated.

Re: Problems putting KL03 into VLPS and reducing power consumption

rickstuart — Tue, 31 Mar 2015 03:49:36 GMT

I don't have my code w/me right now so I'm guessing and will probably edit this post tomorrow if I find time.

I don't think you need to switch to the lower 8/2MHz clock just to get into Very Low Power Stop. If true, then it is very suspicious that when you are in VLPS, picking a different clock speed changes the processor's current demand.

> The code I'm using is in my original post and it matches the SDK code that

> Jeremy pointed me too and other sample codes I found in the community.

I scanned your code again. I don't see the SPI interrupt service routine.

Also, have you been able to break using the debugger inside your SPI interrupt service routine?

> Only when I switch to the lower clock that the SPI doesn't wake up.

You mean SPI doesn't work at alll? Even w/o going into VLPS? I missed this the 1st time. You might check the clock block diagrams to see where the SPI is getting it's clock. It might be that messing with the processor clock breaks the SPI feature. That is, messing with the processor clock requires you to adjust the SPI clock settings so as not to break the SPI when selecting the 8/2MHz clock for the processor.

Edit (added later):

I checked and it appears that I can run 48MHz, drop into VLPS w/no 8/2MHz clock running and get down to ~5uA. If I leave the 2/8MHz clock running at 2MH to drive TPM0 I can only get down to ~20uA. But now I have a much more accurate clock to wake me up from VLPS mode. If you can get SPI working at 48MHz I would try not to complicate things by switching to the 8/2MHz clock. Or accidentally leave the 8/2MHz clock running while in VLPS mode. Besides, you indicated that SPI only works at 48MHz and not when using the 8/2MHz clock.

Note: I would also disable any testing (unnecessary) output pins and mux settings that steer clocks to these output pins. I find that driving pins with clocks takes way more current that I had expected. These are things I did for testing. I don't think the default (power up) state of the processor drives any pins with clocks.

Looking at your code:

You are doing this:

SMC_PMPROT = (SMC_PMPROT_AVLP_MASK | SMC_PMPROT_AVLLS_MASK);

I'm only doing this:

SMC_PMPROT=SMC_PMPROT_AVLP_MASK

Not sure you need this function (i.e. not sure you need to do what is in this function):

vlps_exit()

You may be missing either this:

SPI0_IRQHandler()

...or this:

SPI1_IRQHandler()

...I think it depends on how new the support code for you processor is. These are the names given the SPI interrupt handler in the startup_MKL27Z644.s file for the '27 processor. I assume Freescale uses the same name(s) (I don't know how many SPI ports an '03 has) for the '03.

Re: Re: Problems putting KL03 into VLPS and reducing power consumption

jeremyzhou — Tue, 31 Mar 2015 06:41:03 GMT

Hi Will,

I was wondering if you can share the whole demo, then I can run it with FRDM-KL03 board for checking.

I'm looking forward to your reply.
Have a great day,
Ping

Re: Problems putting KL03 into VLPS and reducing power consumption

willx — Wed, 01 Apr 2015 22:54:11 GMT

Hey Jeremy,

Here's the code I have. I trimmed down my project to this and I'm still seeing 0.9mA.

void vlps_enter(void)

{

SMC_PMCTRL = SMC_PMCTRL_STOPM(2));

dummyread = SMC_PMCTRL;

(void)dummyread;

SCB_SCR |= SCB_SCR_SLEEPDEEP_MASK;

dsb();

wfi();

isb();

}

void vlps_exit(void)

{

SMC_PMCTRL &= ~SMC_PMCTRL_STOPM_MASK;

SCB_SCR &= ~(SCB_SCR_SLEEPDEEP_MASK | SCB_SCR_SLEEPONEXIT_MASK);

}

void set_HIRC(void)

{

MCG_MC |= MCG_MC_HIRCEN_MASK;

MCG_C1 = MCG_C1_CLKS(0);

MCG_C2 = 0;

while (((MCG_S & MCG_S_CLKST_MASK) >> MCG_S_CLKST_SHIFT) != 0x00);

}

void set_LIRC(void)

{

MCG_MC = 0;

MCG_C1 = MCG_C1_CLKS(1);

MCG_C2 = 0;

while (((MCG_S & MCG_S_CLKST_MASK) >> MCG_S_CLKST_SHIFT) != 0x01);

}

void main()

{

/* Set the KL03 clock to be the max at 48MHz */

set_HIRC();

SMC_PMPROT = SMC_PMPROT_AVLP_MASK;

while(1)

{

set_LIRC();

vlps_enter();

// KL03 is in VLPS here

vlps_exit();

set_HIRC();

}

If I comment out the 2 calls to set_LIRC() and set_HIRC() inside of the while loop, I get a power consumption of 1.6mA.

Re: Problems putting KL03 into VLPS and reducing power consumption

willx — Wed, 01 Apr 2015 22:56:40 GMT

Thanks for your help Rick.

Here's the code I have and that I just replied to Jeremy with. I trimmed down my project to this and I'm still seeing 0.9mA. I'll deal with the SPI issue once I'm able to get to a low power number (I have a SPI IRQ handler SPI0_IRQHandler() but didn't mention it in my original post).

void vlps_enter(void)

{

SMC_PMCTRL = SMC_PMCTRL_STOPM(2));

dummyread = SMC_PMCTRL;

(void)dummyread;

SCB_SCR |= SCB_SCR_SLEEPDEEP_MASK;

dsb();

wfi();

isb();

}

void vlps_exit(void)

{

SMC_PMCTRL &= ~SMC_PMCTRL_STOPM_MASK;

SCB_SCR &= ~(SCB_SCR_SLEEPDEEP_MASK | SCB_SCR_SLEEPONEXIT_MASK);

}

void set_HIRC(void)

{

MCG_MC |= MCG_MC_HIRCEN_MASK;

MCG_C1 = MCG_C1_CLKS(0);

MCG_C2 = 0;

while (((MCG_S & MCG_S_CLKST_MASK) >> MCG_S_CLKST_SHIFT) != 0x00);

}

void set_LIRC(void)

{

MCG_MC = 0;

MCG_C1 = MCG_C1_CLKS(1);

MCG_C2 = 0;

while (((MCG_S & MCG_S_CLKST_MASK) >> MCG_S_CLKST_SHIFT) != 0x01);

}

void main()

{

/* Set the KL03 clock to be the max at 48MHz */

set_HIRC();

SMC_PMPROT = SMC_PMPROT_AVLP_MASK;

while(1)

{

set_LIRC();

vlps_enter();

// KL03 is in VLPS here

vlps_exit();

set_HIRC();

}

If I comment out the 2 calls to set_LIRC() and set_HIRC() inside of the while loop, I get a power consumption of 1.6mA.

Re: Problems putting KL03 into VLPS and reducing power consumption

jeremyzhou — Thu, 02 Apr 2015 07:02:47 GMT

Hi Will X,

I'm working on this code now and I'll inform you ASAP if I work it out.

And you can also share some updating in the community.
Have a great day,
Ping

Re: Problems putting KL03 into VLPS and reducing power consumption

willx — Thu, 02 Apr 2015 18:40:37 GMT

Btw, I just ran that snippet of code on a FRDM-KL03Z board measured the power consumed by the KL03 alone (through jumper J10) and I'm seeing the same numbers: 0.9mA when switching from HIRC to LIRC2M and 1.6mA if not touching the clocks.

Re: Problems putting KL03 into VLPS and reducing power consumption

willx — Mon, 06 Apr 2015 20:32:35 GMT

Hi Jeremy,

Were you able to run my code on your end and measure the power consumption?

Thanks!

Re: Problems putting KL03 into VLPS and reducing power consumption

jeremyzhou — Tue, 07 Apr 2015 06:02:29 GMT

Hi Will,

I've got the different result from you, I used the code from the SDK instead of yours, then the current consumption will drop to 1.85uA when the MCU entered the VLPS mode.

I ran the code on the FRDM-KL03Z board.

Wish it helps.
Have a great day,
Ping

Re: Problems putting KL03 into VLPS and reducing power consumption

willx — Tue, 07 Apr 2015 17:17:16 GMT

Thanks for letting me know.

Can you point me to exactly which sample code from the SDK you used? There's a ton of examples there so pointing me to the one you ran would be great.

Re: Problems putting KL03 into VLPS and reducing power consumption

jeremyzhou — Wed, 08 Apr 2015 02:15:21 GMT

Hi Will,

FSL's shared a Kinetis SDK_1.0.0 Standone for FRDM-KL03Z and it includes a low_power_rtc demo which illustrates the ways to enter and exit different low power modes.

This demo resides in ~\Freescale\KSDK_1.0.0-KL03Z\demos and you can download the SDK through the link as below.

https://cache.freescale.com/secured/sdk/Freescale_KSDK_1.0.0-KL03Z.exe?__gda__=1428466397_9bc09e3adb75fdecb1bedf0dfc9a19…

Hope it helps.
Have a great day,
Ping

Re: Problems putting KL03 into VLPS and reducing power consumption

willx — Wed, 08 Apr 2015 23:47:50 GMT

Thanks Jeremy.

I am trying to look into that but that SDK is a total mess. And me development environment is on Mac so I'm having a lot of problems to figure out how to load it on the FRDM-KL03Z.

Are you able to load my code and run it yourself?

void vlps_enter(void)

{

SMC_PMCTRL = SMC_PMCTRL_STOPM(2));

dummyread = SMC_PMCTRL;

(void)dummyread;

SCB_SCR |= SCB_SCR_SLEEPDEEP_MASK;

dsb();

wfi();

isb();

}

void vlps_exit(void)

{

SMC_PMCTRL &= ~SMC_PMCTRL_STOPM_MASK;

SCB_SCR &= ~(SCB_SCR_SLEEPDEEP_MASK | SCB_SCR_SLEEPONEXIT_MASK);

}

void set_HIRC(void)

{

MCG_MC |= MCG_MC_HIRCEN_MASK;

MCG_C1 = MCG_C1_CLKS(0);

MCG_C2 = 0;

while (((MCG_S & MCG_S_CLKST_MASK) >> MCG_S_CLKST_SHIFT) != 0x00);

}

void set_LIRC(void)

{

MCG_MC = 0;

MCG_C1 = MCG_C1_CLKS(1);

MCG_C2 = 0;

while (((MCG_S & MCG_S_CLKST_MASK) >> MCG_S_CLKST_SHIFT) != 0x01);

}

void main()

{

/* Set the KL03 clock to be the max at 48MHz */

set_HIRC();

SMC_PMPROT = SMC_PMPROT_AVLP_MASK;

while(1)

{

//set_LIRC();

vlps_enter();

// KL03 is in VLPS here

vlps_exit();

//set_HIRC();

}

Re: Re: Problems putting KL03 into VLPS and reducing power consumption

jeremyzhou — Thu, 09 Apr 2015 09:19:37 GMT

Hi Will,

Please use these simply codes as below to enter the VLPS mode and wish it helps.

void Ready_vlpr(void)
{
    SIM_CLKDIV1|=(SIM_CLKDIV1_OUTDIV4(3) | SIM_CLKDIV1_OUTDIV1(1));
}


int enter_vlpr(void)
{
  int i;
  unsigned int return_value = 0;  //default return value = indicates error
  if ((SMC_PMSTAT & SMC_PMSTAT_PMSTAT_MASK)== 4){
        return_value = 0x14;
        }
  /* The PMPROT register may have already been written by init code
    If so then this next write is not done. 
    PMPROT is write once after RESET 
    this write-once bit allows the MCU to enter the
    very low power modes: VLPR, VLPW, and VLPS  */
  SMC_PMPROT = SMC_PMPROT_AVLP_MASK; 
   
  /* Set the (for MC1)LPLLSM or (for MC2)STOPM field
    to 0b010 for VLPS mode -
    and RUNM bits to 0b010 for VLPR mode  */
  SMC_PMCTRL &= ~SMC_PMCTRL_RUNM_MASK;
  SMC_PMCTRL  |= SMC_PMCTRL_RUNM(0x2);
  /* Wait for VLPS regulator mode to be confirmed */
  for (i = 0 ; i < 10000 ; i++)
    {    /* check that the value of REGONS bit is not 0
            once it is a zero we can stop checking */
      if ((PMC_REGSC & PMC_REGSC_REGONS_MASK) ==0x04){
      /* 0 Regulator is in stop regulation or in transition
            to/from it
          1 MCU is in Run regulation mode */
      } 
      else  break;
    } 
  if ((PMC_REGSC & PMC_REGSC_REGONS_MASK) ==0x04)
    { 
      return_value = 0x24;
    }
  /* SMC_PMSTAT register only exist in Mode Controller 2 MCU versions */
  if ((SMC_PMSTAT & SMC_PMSTAT_PMSTAT_MASK) == 4) 
    {
      return_value = SMC_PMSTAT;
    }
  return (return_value);
}


void enter_vlps(void)
{
  volatile unsigned int dummyread;
  /* The PMPROT register may have already been written by init code
    If so then this next write is not done since 
    PMPROT is write once after RESET
    allows the MCU to enter the VLPR, VLPW, and VLPS modes.
    If AVLP is already writen to 0
    Stop is entered instead of VLPS*/
  SMC_PMPROT = SMC_PMPROT_AVLP_MASK;         
  /* Set the STOPM field to 0b010 for VLPS mode */
  SMC_PMCTRL &= ~SMC_PMCTRL_STOPM_MASK;
  SMC_PMCTRL |=  SMC_PMCTRL_STOPM(0x2);
  /*wait for write to complete to SMC before stopping core */ 
  dummyread = SMC_PMCTRL;
  dummyread++;
  /* Now execute the stop instruction to go into VLPS */

  /* Set the SLEEPDEEP bit to enable deep sleep mode (STOP) */
  SCB_SCR |= SCB_SCR_SLEEPDEEP_MASK;
  __wfi();
}

/*----------------------------------------------------------------------------
  MAIN function
*----------------------------------------------------------------------------*/
int main (void)
{
  Ready_vlpr();//Busclk = 8Mhz/2 /2 /4= 500K
  enter_vlpr();
  enter_vlps();
}

Have a great day,
Ping

Re: Problems putting KL03 into VLPS and reducing power consumption

rickstuart — Thu, 09 Apr 2015 16:48:40 GMT

Ping,

I can not get the FRDM-KL03Z to draw less than 250uA. I used your software from above but had make 4 changes:

1) added #include "MKL03Z4.h"

2) added #include "core_cm0plus.h"

3) removed KL03Z/lib/ksdk_platform_lib/iar/KL03Z4/debug/ksdk_platform_lib.a from library list.

4) changed "__wfi();" to "__asm("WFI");"

I programmed the LK03 processor, disconnected the debugger, then removed and restored power.

Do you have any suggestions?

-thanks