Esp32-s2 Co-processor does not shutdown with shutdown command

DylanWork
Posts: 32
Joined: Wed Jun 02, 2021 4:27 am

Esp32-s2 Co-processor does not shutdown with shutdown command

Postby DylanWork » Tue Jan 11, 2022 3:30 am

Hi all,

Running similar code to this example and using the functions:
ulp_riscv_wakeup_main_processor();
ulp_riscv_shutdown();

I would have expected the shutdown function to do exactly as described and the co-processor more into HALT state or just off altogether and not run until initiated in the main CPU.

However this is not the case as demonstrated during power consumption measurements I have taken where the co-processor is meant to turn off while the main CPU is on. I am pulsing LED's during this period which makes it clear that the ULP remains on. I have attached an image showing the ULP and Main processor working at the same time even though the shutdown command is called at the same time as the wake_main_processor command.

When diving into the ulp_riscv_shutdown() function:

Code: Select all

void ulp_riscv_shutdown(void)
{
    /* Setting the delay time after RISCV recv `DONE` signal, Ensure that action `RESET` can be executed in time. */
    REG_SET_FIELD(RTC_CNTL_COCPU_CTRL_REG, RTC_CNTL_COCPU_SHUT_2_CLK_DIS, 0x3F);

    /* suspends the ulp operation*/
    SET_PERI_REG_MASK(RTC_CNTL_COCPU_CTRL_REG, RTC_CNTL_COCPU_DONE);

    /* Resets the processor */
    SET_PERI_REG_MASK(RTC_CNTL_COCPU_CTRL_REG, RTC_CNTL_COCPU_SHUT_RESET_EN);

    while(1);
}
The technical reference guide shows this as how the shutdown process should occur:
Before setting ULP-RISC-V to HALT, users should configure the register RTC_CNTL_COCPU_DONE first,
therefore, it is recommended to end the flashed program with the following pattern
– Set the register RTC_CNTL_COCPU_DONE to end the operation of ULP-RISC-V and put it into halt;
– Set the register RTC_CNTL_COCPU_SHUT_RESET_EN to reset ULP-RISC-V
(See Page 30)
If I remove the line for resetting the processor, the Co-processor crashes.
If I change:
SET_PERI_REG_MASK(RTC_CNTL_COCPU_CTRL_REG, RTC_CNTL_COCPU_SHUT_RESET_EN);
To
SET_PERI_REG_MASK(RTC_CNTL_COCPU_CTRL_REG, RTC_CNTL_COCPU_SHUT);
The co-processor crashes.

My question is simple, how do I turn off the co-processor?

Cheers,
Dylan
Attachments
MCUandULP.png
MCUandULP.png (25.96 KiB) Viewed 4798 times

DylanWork
Posts: 32
Joined: Wed Jun 02, 2021 4:27 am

Re: Esp32-s2 Co-processor does not shutdown with shutdown command

Postby DylanWork » Thu Jan 13, 2022 1:25 am

Hi all,

Just bumping this and hoping to ask an open question to whoever is looking through my posts.

I have posted a few questions relating to the ESP32-S2 co-processor and related items, but I don't appear to be getting answers.

Am I not giving enough detail, or is my posting style confusing, or is this topic just more technical than people are able to answer?

Would be great if I could get any response even if it's just "Sorry, too hard" or "You don't make any sense".

Cheers,
Dylan

ESP_Sprite
Posts: 9709
Joined: Thu Nov 26, 2015 4:08 am

Re: Esp32-s2 Co-processor does not shutdown with shutdown command

Postby ESP_Sprite » Thu Jan 13, 2022 9:48 am

I think it's too technical. Given the fact that this can be seen as a bug (as in: a function that purports to shut down the ULP does not do that), you may have more luck posting it on the ESP-IDF Github repo as an issue.

DylanWork
Posts: 32
Joined: Wed Jun 02, 2021 4:27 am

Re: Esp32-s2 Co-processor does not shutdown with shutdown command

Postby DylanWork » Thu Jan 13, 2022 12:15 pm

Ok, thank you for responding.

I'll submit an issue on github and post back here when it gets resolved to help with anyone in the future.

Cheers,
Dylan

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