J784S4XEVM: Suspend to RAM and Wakeup enable via CAN for PMIC IC TPS6594133ARWERQ1 in J784S4XEVM.

Hi,

Our expect is on vacation this week, Kindly wait for response.

Best Regards,
Sudheer

Hello Tanishq,

Thanks for your patience. What os are you using for the suspend to ram? Are you using Linux? Or is this your own bare metal implementation of s2r?

Best Regards,

Keerthy

Hello Keerthy J,

Thank you for your response. Yes, we are currently using Linux as the OS for our S2R implementation. We would like to confirm that our approach aligns with TI's recommended method for this platform, and also request your support for configuring CAN wake-up from Suspend to RAM. Additionally, if possible, we would appreciate the opportunity to schedule a call to discuss our implementation and clarify a few details more effectively.

Regards,

Tanishq Kanungo

Hello Nicholas McNamara,  Keerthy J,

Thank you for the details provided. Please find our response below:
1. Target PDN: We are using PDN-3A for this system.
2. Target Wake-up State: The intended wake-up destination state is Full Active. we verified the RTC_CTRL_2 (C3h) register value as 0xE1, confirming the correct Wake-up State configuration.

GPIO_6 is configured as REGEN with open-drain output, per NVM default settings. The DDR_RET flow is properly implemented, and we are successfully transitioning into Suspend-to-RAM (S2R) mode

Request for Guidance on CAN Wake via GPIO_4 (LP_WKUP1):
We would appreciate guidance for correctly setting up the CAN wake-up mechanism using GPIO_4 (LP_WKUP1). We understand that a signal edge toggle on GPIO_4 is required to trigger exit from DDR_RET and resume to Full Active mode.
We would appreciate support in configuring the software stack to enable CAN-based wake-up.

Specifically:
How to properly configure the wake-up frame on the CAN controller to detect the CAN_WAKE signal via GPIO_4(LP_WKUP1).
Is there a reference waveform or timing requirement for the CAN_WAKE signal to be recognized by LP_WKUP1?
Your assistance with completing the wake-up via CAN is greatly appreciated.

Regards,

Tanishq Kanungo

Hello Tanishq,

I'll be referring to this User's Guide for the PMIC here, with software instructions necessary to wake from the GPIO_4 pin: https://www.ti.com/lit/ug/slvuci2/slvuci2.pdf?ts=1745475706576

The above comes from the User's Guide.

As for the software needed for the CAN controller running on the J7 side, Keerthy can make comments on that.

BR,

Nicholas

Hello Hello Nicholas McNamara,  Keerthy J,

I have also referred the same user guide for S2R/Retention mode. I have followed the below listed same sequence of command to successfully transitioning into Suspend-to-RAM (S2R) mode.

I would appreciate your assistance in wakeup from retention using GPIO_4 triggered by CAN WUP frame.

Regards,

Tanishq Kanungo

Tanishq,

The IO Retention mode is currently not supported in the SDK. Are you able to wake up the system from S2R mode using external wake up like PMIC GPIO? 

Best Regards,

Keerthy 

Tanishq,

The IO Retention mode is currently not supported in the SDK. Are you able to wake up the system from S2R mode using external wake up like PMIC GPIO? 

Best Regards,

Keerthy 

Hello Keerthy, Nicholas McNamara,

We are currently trying to wakeup from the S2R mode via CAN. As a part of this, we have identified that the PMIC wake up signal is routed to GPIO_4 (LP_WKUP1). our understanding is that a signal edge toggle on GPIO_4 is required to trigger exit from DDR_RET and resume to Full Active mode. We have also confirmed that INH pin (CAN_WKUP) of the TCAN1043-Q1 transceivers is connected to GPIO_4. This setup allows us to use the CAN transceiver to generate the necessary edge signal. To wakeup from S2R we plan to send the Wakeup frame to the TCAN1043-Q1 transceiver.

However, we observed that the MAIN_CAN3 interface, which is required to send the wakeup frame, is currently not enabled in the device driver. We would appreciate support in configuring the software stack to enable CAN-based wake-up. 

We would also like to request a call with TI team to discuss and for further analysis.

Regards,

Tanishq Kanungo.

Tanishq,

Are you targeting an external wakeup or an Internal IO Wakeup? We do not have this implementation and without that I really cannot comment here.

- Keerthy

Hello Keerthy,

we are targeting an external wakeup via CAN. 

Regards,

Tanishq

Hello @Keerthy,

Can we have a short call with your time. We have made necessary changes in SDK required. We would like to confirm if anything is missing. Also, would like to understand whether wakeup from S2R is possible on evalkit without any changes in PCB. We would like to discuss the issue.

Regards,
Geoff

Hi Geoff,

Geoff Roy said:

Also, would like to understand whether wakeup from S2R is possible on evalkit without any changes in PCB

There are some hardware changes required, but no changes in PCB required. The changes required are : 

 On PROC141E3 / J784S4XG01EVM and PROC141E4 / J784S4XG01EVM with these hardware changes:

1. Mandatory: R658 moved to R659 (0 Ohm)
   1. Without this change, the board won't stay in suspend
2. May not be necessary: Change R534 from pull-down to pull-up to VCCA_3V3 side of C320

These changes are not the same for PROC141E2 / J784S4XG01EVM and PROC141E2A / J784S4XG01EVM.

1. There will be additional changes required for the above boards which have not been worked out.
2. There are two circuits driving the "SOC_PWR_WKn" signal in E3 and E4. This signal goes to PMIC and is required for waking up the SoC. Change 1 disables one of the circuit.

One more thing to note would be that we have only verified wake from GPIO sources and not from TCAN signals. But in theory, if GPIO pins and TCAN's effect on SOC_PWR_WKn is same, there is no reason CAN shouldn't work.

Regards,
Tanmay

Hello Tanmay,

Will check on hardware changes. Thanks for the info, this might help. 
We have both PROC141E5/J784S4XG01EVM and  PROC141E4/J784S4XG01EVM. Currently, testing is performed on  PROC141E4/J784S4XG01EVM.
Does PROC141E5/J784S4XG01EVM also require hardware changes?

If you can share your mail id it would be helpful.

Regards,
Geoff
mail: geoff.ar@tcs.com

Hello @Tanmay,

Sequence followed : Transceiver enters sleep state -> S2R activated.
Observation: VCC_12V0 is turned off. Fan stops. 

• When S2R is performed after transceiver enters Sleep, Vcc_12V_0 is turned off(current consumption is reduced to zero with status LED active). Unable to do wakeup in this condition. (Wake pin is low). When SW15 is pressed current fan starts and current consumption rises to 0.3A.
• When S2R is performed without transceiver entering sleep, current consumption is 0.3A VCC_12V_0 is active.

Our intention is to wakeup the system from DDR retention to Active using CAN frame on MCAN3..  If R658 is removed, I guess it will not help in CAN based wakeup. 

Also, are you referring to Change 1 + usage of PB_CAN_WAKEn  Switch as GPIO wakeup which was verified.

Regards,
Geoff