S32KのトピックRe: s32k standby

s32k standby

fengba_360 — Tue, 05 Nov 2024 01:15:11 GMT

Hello, I have a few questions while using the standby mode of S32K312:

1.What is the relationship between enabling the clock for MCU peripherals within the power management module and enabling the clock within the clock group? If I enable the clock within the clock group, do I still need to enable it in run mode?
2.For standby mode, if I use CAN to wake up the MCU, I noticed in the example routine that the flexcan0 clock within the MCU peripheral of the power management module is not enabled in standby mode. Is this configuration unnecessary?
3.If I want to use a specific CAN ID to wake up the MCU, do I only need to implement the relevant logic for judgment in the CAN 0 callback function?
Thank you for your help.

Re: s32k standby

Julián_AragónM — Tue, 05 Nov 2024 19:01:22 GMT

Hi @fengba_360,

1. Even if you are not using the POWER component, you can still enable and disable application cores and peripherals as needed, based on functional and power requirements.

For example, in the S32K3 Low Power Management AN and demos, a second functional group is used to enter the VLSR mode by simply switching the clock from PLL to FIRC:

The clock tool enables the clocks, and the power component enable the fields that gate the application core clocks, which can also be clock gated by executing Waiting for Interrupt (WFI). You can look at Chapter 46 from the S32K3XX's reference manual for more information.

If you use the power driver and set a power mode, you need to configure the peripherals used in that specific mode, using that same low power demos, you can see that the power driver is initialized, and the RUN mode is set:

This driver then configures the peripheral clock gating with the configuration set in "McuPeripheral".

2. Since FlexCAN itself is not a power domain, the module is not used for wakeup and does not need to be enabled for standby, only the external pin is used as interrupt which shares the FlexCAN functionality. Please refer to this post: Solved: Re: S32K3 Wake up method - NXP Community.

3. Since FlexCAN module does not provide wakeup, yes, functionality must be implemented in the callback.

Best regards,
Julián

Re: s32k standby

fengba_360 — Wed, 06 Nov 2024 00:53:45 GMT

So, I can't configure FlexCAN to wake up upon receiving a specific CAN ID (such as 0x55), right?

Re: s32k standby

fengba_360 — Wed, 06 Nov 2024 11:43:50 GMT

I have been able to use the standby mode, but I encountered a problem. I selected two GPIOs (PTB28, PTC18) as wake-up sources, with PTC18 as the sleep control pin. When PTC18 is low, the S32K312 enters standby mode. At this point, if I provide a high level to PTC18, the S32K312 can be woken up, but a high level on PTB28 does not wake it up. When PTC18 is high, the S32K312 also enters standby mode. However, at this point, a low level on PTC18 cannot wake up the S32K312, but a low level on PTB28 can normally wake it up. Can you tell me the reason for this?

Additionally, does it support wake-up triggered by a specific CAN ID?

Re: s32k standby

Julián_AragónM — Thu, 07 Nov 2024 18:02:13 GMT

Hi @fengba_360,

I'm not sure I understand your issue, are the wakeup sources not working when done at the same time?

Also, no, as I've said, the FlexCAN module does not support wake up, so no specific CAN ID can be used for wake up, but you can use a callback to compare IDs.

Best regards,
Julián

Re: s32k standby

fengba_360 — Mon, 11 Nov 2024 00:52:51 GMT

Thank you. Now I can work normally in standby mode. Regarding CAN wakeup, my understanding is that it can only detect rising and falling edges to trigger wakeup, and after wakeup, it will then detect the ID. If there is no corresponding ID, it will enter sleep mode again. Is that right? Thank you!

Re: s32k standby

Julián_AragónM — Mon, 11 Nov 2024 16:07:27 GMT

Hi @fengba_360,

Yes, you are correct. You can configure the application to read the ID and if it is not the specified ID, you can make the board go to standby again.

Best regards,
Julián