Determining Wakeup Source

Micheal Donohuue

Hi,

I have a AM335X board running SDK8, I'm running a Qt application on this and one of my requirements is the sound an alarm upon resume from deepsleep0 if the wakeup source is an RTC alarm. I'm just wondering if there is a way to determine the wakeup source from User space?

Thanks

Micheal

over 10 years ago

0 Titusrathinaraj Stalin over 10 years ago

TI__Guru** 116100 points

Hi,
No, we can't wakeup the device from userspace since it is completely shutdown.
We have 2 options to wakeup the SoC from DEEPSLEEP.
1) By external controller (Need rise/fall edge trigger at dedicated GPIO pin by external controller)
2) RTC alarm as you said.

Please refer to the power management chapter of TRM.

0 Micheal Donohuue over 10 years ago in reply to Titusrathinaraj Stalin

Intellectual 470 points

Hi,

What I am wondering is can I determine from Userspace after a resume whether the device was woken by an Alarm or by a GPIO? The problem I have at the moment is I don't know if the power button or the alarm woke the device and have to do a compare of the rtc wakealarm to current time which isn't ideal.

Thanks

Micheal

0 Micheal Donohuue over 10 years ago in reply to Micheal Donohuue

Intellectual 470 points

Hi,

Is there any information you can give me on the above?

Thanks

0 Titusrathinaraj Stalin over 10 years ago in reply to Micheal Donohuue

TI__Guru** 116100 points

Hi Micheal,

Apologize for the delayed response on this.

Let me correct first, I've checked the TRM of AM335x, I noted that you can also wakeup the SoC from DEEPSLEEP mode by the following events,

• GPIO0 bank
• dmtimer1_1ms (timer based wakeup)
• USB2PHY (USB resume signaling from suspend) – Both USB ports supported.
• TSC (touch screen controller, ADC monitor functions )
• UART0 (Infra-red support)
• I2C0
• RTC alarm

Please refer to the chapter 8.1.4.5

What I am wondering is can I determine from Userspace after a resume whether the device was woken by an Alarm or by a GPIO? The problem I have at the moment is I don't know if the power button or the alarm woke the device and have to do a compare of the rtc wakealarm to current time which isn't ideal.

Let me check with appropriate team.

0 Micheal Donohuue over 10 years ago in reply to Titusrathinaraj Stalin

Intellectual 470 points

Hi Titus,

Have you any update on this?

Regards
Micheal

0 Paul_baw over 8 years ago in reply to Titusrathinaraj Stalin

Prodigy 40 points

I would also be interested on a definitive answer on this (old) question. Looking at the Kernel Code and the TRU, it seems no possibility exists.

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Determining Wakeup Source