Stop mode

[stabilo]

Hello,

Could you please explain me what are the steps to enter into stop mode ? Currently, I write "1" into SLEEPDEEP. SMC registers (STOPCTRL and STOPM) are configured to enter to STOP mode when Sleep-On-Exit or Sleep-Now mode is entered with SLEEPDEEP = 1 (cf datasheet). But what is actually Sleep-On-Exit and Sleep-Now ? and how can we set them ?  

Thank you

[stabilo]

Hello,

The RAM is still active in VLPS mode, I mean when the MCU wakes up, the content of the RAM is not lost ?

Thank you

[danielmartynek]

Hi,

Yes, RAM retained in all modes, see Table 34-1 in the RM.

Regards,

Daniel

[stabilo]

Hello,

Do you have any additional information about the "Normal stop mode" ? I am currently using 0N77P and I don't understand why my consumption is higher when I use the stop mode 1 or the stop mode 2. When using VLPS, is possible to wakeup using LPIT or PORT interrupt ?

Thank you

[danielmartynek]

Hi,

Unfortunately, I don’t have any information.

If you look at current S32K1xx Data Sheet, which you can find on the product page, the typical power consumption (chapter 4.7) is given only for VLPS(39.1uA), STOP1(7mA) and STOP2(7.7mA).

You should be able to wake up from VLPS using GPIO, ADC, CMP and LPTMR instead of LPIT.

Regards,

Daniel

[stabilo]

Hi,

Does the CAN peripheral needs the bus clock to wakeup from stop mode ? When i'm using the STOP2 mode, the MCU can be woken up by a CAN message, but when using STOP1 mode, the MCU never wakes up. I need to optimize the current consumption during STOP mode, and when the bus clock is disabled, I save 200uA.

Thank you

[danielmartynek]

Hi

As per the reference manual you can use Pretended Networking (for CAN0 only) which should be supported in both modes STOP1/STOP2.

Pretended Networking mode adds specific wake up functionality in Stop modes. CHI sub-block clocks are shut down and CAN_PE sub-block is kept clocked, so that the Rx receive process is still active to filter incoming messages. Upon detecting a wake-up event, a Wake-up interrupt is issued to the system. 

Regards

Daniel

[amZ1]

Hello, I'm trying to use the S32K148 to enter stop mode and wake up with a CAN interrupt. I activated the pretend networking and CanIcom to select a source of wake-up from EcuM.

In debugging, I can see that I enter stop mode 1, but I never succeed in waking up while sending CAN messages (the CAN bus is always heavy when I try to send CAN messages). I don't know what I have to do to exit stop mode.

[stabilo]

Hello,

In my datasheet (revA), I can configure the normal stop mode and it works:

So I don't know if it is an error in the datasheet.

The problem with the VLPS stop mode is that I cannot wake up using an external interrupt for example.

[danielmartynek]

Hi

I checked all reference manuals and only S32K144_0N77P_Mask_only RM and RevA, which is also for N77P, support the option. Whereas Rev1.0 and Rev2.0 (for newer 0N47T mask set) don’t.

I’ll try to find more information.

Daniel

[stabilo]

Hello,

Thank you for your help. I have one additional question: what happen if PSTOPO is set to 0 ? (normal Stop mode). Because in this mode, the consumption is very low and I still can wake up from sleep using an internal timer or by port interrupt. When I use STOP1 or STOP2 mode, the consumption is too high.  How can I reduce the consumption if I use STOP1 or STOP2 ?

[danielmartynek]

Hi

According to the datasheet, if Normal Stop Mode is set (PMCTRL[STOPM = 0b000]), the STOPO bits in the STOPCTRL register must be used to select the variants of stop - STOP1/STOP2. STOPO(0b00) is reserved.

The consumption varies depending on peripherals you use. See chapter 33.8 Module operation in available low power modes in the datasheet. And compare VLPS and STOP mode.

Regards

Daniel      

[danielmartynek]

Hi

Sleep-On-Exit and Sleep-Now are ARM core stop modes. Both modes wake up the MCU when an interrupt occurs. The only difference between these two modes is that Sleep-On-Exit returns back to the stop mode when exiting an interrupt handler.

Sleep-Now is set by default. To set Sleep-On-Exit use:

S32_SCB->SCR |= S32_SCB_SCR_SLEEPONEXIT_MASK;

The example project attached shows all steps to enter various stop modes.

Regards Daniel