PMIC TPS65910A3A1RSL

Hi Shabbir,

Yes, it's possible. This can be done either by a power button, if you have one in your design, or by software command. For the second case you will need to connect the PWRHOLD input to the AM335X PMIC_POWER_EN output.

Hi Biser,

Yes we have power button connected to PMIC's PWRON pin. But it is not satisfying our requirement. Where I press it, nothing effective happen.

Thanks,

Shabbir Limdiwala

You have to press and hold for >8sec to turn off the PMIC.

Hi Biser,

Thanks for the support.

How to power off the board using software command making use of AM335X PMIC_POWER_EN pin ?

I have gone through TRM but i didn't find any way to doing that.

Thanks and Regards,

Shabbir Limdiwala

Shabbir, what software and what software version are you using?

If using Linux, the user space command to shut down the system is: "shutdown"

Type "shutdown" to see the available options.

Best regards,
Miroslav

As for the board shutdown, it can be done via the RTC's ALARM2 registers.

I'm not aware if there is a user-space tool in our SDK that does this, but you can check these useful topics:

http://minix-i2c.blogspot.com/2013/07/software-power-off-of-am335x-with.html

https://groups.google.com/forum/#!topic/rtc-linux/cj2UnFPRdcc

Best regards,
Miroslav

Hi Miroslav,

We are using ti-sdk-am335x-evm-06.00.00.00/ software package. We have modified kernel image as per our customize design. The rest is as it is.

I use shutdown and it gives help manual as follows,

Usage:    shutdown [-akrhPHfFnc] [-t sec] time [warning message]
                  -a:      use /etc/shutdown.allow
                  -k:      don't really shutdown, only warn.
                  -r:      reboot after shutdown.
                  -h:      halt after shutdown.
                  -P:      halt action is to turn off power.
                  -H:      halt action is to just halt.
                  -f:      do a 'fast' reboot (skip fsck).
                  -F:      Force fsck on reboot.
                  -n:      do not go through "init" but go down real fast.
                  -c:      cancel a running shutdown.
                  -t secs: delay between warning and kill signal.
                  ** the "time" argument is mandatory! (try "now") **

None of the option is working.

Thanks and Regards,

Shabbir Limdiwala

Hi Biser and Miroslav,

We used am335x sitara evm's design as a reference in our custom design. So before performing power off experiment in our custom design, i tried to perform same experiment in evm first.

Evm has power button which successfully power off the board after pressing it for more then 8 secs.

Now I tried to power off the board using software command which is poweroff. This command shows following logs,

Deactivating swap...
Unmounting local filesystems...
[   41.088073] musb-hdrc musb-hdrc.1: remove, state 1
[   41.093170] usb usb1: USB disconnect, device number 1
[   41.099090] musb-hdrc musb-hdrc.1: USB bus 1 deregistered
[   41.105163] System halted.

This command didn't work because power off is not supported in rtc-omap driver. So I enabled the power off support in board file as follows arm/arch/mach-omap2/board-am335xevm.c,

static struct omap_rtc_pdata am335x_rtc_info = {
//        .pm_off         = false,

        .pm_off         = true,
        .wakeup_capable = 0,
};

and then apply poweroff command which has following logs,

Deactivating swap...
Unmounting local filesystems...
[   42.395385] musb-hdrc musb-hdrc.1: remove, state 1
[   42.400451] usb usb1: USB disconnect, device number 1
[   42.406372] musb-hdrc musb-hdrc.1: USB bus 1 deregistered
[   42.412445] Power down.
[   42.415008] System will go to power_off state in approx. 2 secs

As per the logs support is added successfully but the board didn't got power off state even after more then 2 seconds.

Is there anything that I am missing ? seeking quick response.

Thanks and Regards,

Shabbir Limdiwala

Hi Biser,

In our custom design we have provided power button which connects PWRON pin of the PMIC. But if press for more then 8 seconds, instead of power off, board gets reset.

I have also tried it using software command but in that case also board gets reset.

I am attaching the diagram of PMIC connection with the processor. Can you help us to verify if we are missing anything ?

Thanks and regards,

Shabbir Limdiwala

For PMIC connections to AM335X check this document: http://www.ti.com/lit/ug/swcu093c/swcu093c.pdf

Hi Biser,

We have made connection according to the user guide you mentioned and also match with sitara evm design. But still it's not behaving as per sitara evm.

It would be really appreciable if you can look at it once that what we are still missing ?

Thanks and Regards,

Shabbir Limdiwala