[beagleboard] Re: RTC base address

I am writing values to RTC registers using imd(u-boot command), is it works?

–Sanjeev

— On Tue, 5/5/09, Søren Steen Christensen sorenschristensen@stofanet.dk wrote:


> From: Søren Steen Christensen sorenschristensen@stofanet.dk
> Subject: [beagleboard] Re: RTC base address
> To: beagleboard@googlegroups.com
> Date: Tuesday, 5 May, 2009, 1:06 PM
>
> > What is RTC register address? i want to enable RTC in u-boot?
> > is it possible to enable RTC in u-boot.
>
> The RTC is in the TPS65950-chip, which you can access using the I2C-bus. Take care - It isn’t battery-backed-up and thereby loosing it’s state when the power is removed from the board…
>
> You find information about its registers in the TRM for the TPS65950-chip (http://focus.ti.com/lit/ug/swcu050d/swcu050d.pdf) chapter 3…
>
> Best regards - Good luck
> Søren

|

I am writing values to RTC registers using imd(u-boot command), is it

works?

I would expect so - You might however need to control the mSecure signal
(see TRM and schematics for RevC) to be able to set the RTC value - I can't
remember for sure, but go ahead and give it a try...

Best regards - Good luck
  Søren

I am writing values to RTC registers using imd(u-boot command), is it

works?

I would expect so - You might however need to control the mSecure signal
(see TRM and schematics for RevC) to be able to set the RTC value - I can't
remember for sure, but go ahead and give it a try...

Speaking of the RTC, the Overo brings out the VBACKUP line. Is
providing a battery backup as simple as connecting a suitable battery
(or capacitor), or is there more to it than this?

Philip

>> I am writing values to RTC registers using imd(u-boot command), is
it
> works?
>
> I would expect so - You might however need to control the mSecure
signal
> (see TRM and schematics for RevC) to be able to set the RTC value - I
can't
> remember for sure, but go ahead and give it a try...

Speaking of the RTC, the Overo brings out the VBACKUP line. Is
providing a battery backup as simple as connecting a suitable battery
(or capacitor), or is there more to it than this?

Philip

AFAIR - Connect the battery/capacitor and remember to enable charging using
a couple of I2C writes to TPS65950.

In order to be completely sure - Please double check the TRM and Data
Manual, but straight out of my mind I'm 99.9% confident it's that easy :slight_smile:
  Søren

For those of us who have beagle boards and no rtc, and can't always
rely on ntp. Does anyone have a software solution which can ensure
that we don't have future timestamp problems? I have been running
into this lately where I am compiling programs and "make" sometimes
gets confused and does the wrong thing. I just need to store the time
at shutdown and restore it at boot so I never have files with future
times.

Sean

Op 5 mei 2009 om 14:59 heeft "Sean D'Epagnier"
<geckosenator@gmail.com> het volgende geschreven:\

I just need to store the time
at shutdown and restore it at boot

Angstrom does that by default

And if you are not running Angstrom...

Create a shutdown script that does this

date +%m%d%H%M%Y > /etc/savedate

And in a startup script that does this

date `cat /etc/savedate`

The above is not tested. man date and man strftime will help in
correcting any problems.

-Preston

For what it is worth, so does the REV C3 Beagle, except, it will have an actual battery already soldered in.

Gerald

Hello,

IMHO it would be interesting to have the restore feature done by uboot
if an environment variable like lastknownrtctime exist

Keep saving the time in shutdown somewhere it can be accessed by uboot
(like with setenv), but let it be loaded automagically by uboot if the
parameter is present.

That'd really make the feature distribution independant. I really
prefer avoiding tweaking boot scripts- because then you must make sure
it's done before the fsck, in ro, etc.

For what it is worth, so does the REV C3 Beagle, except,
it will have an actual battery already soldered in.

When will Rev C3 be available - I expect(ed) this to be in the *far* future?
  Søren

Far has many definitions. In this case far would meean we start shipping in a couple of weeks.

Gerald

Cool - I will then wait getting my new Rev C board – Other new hidden features? J

Søren

Well, we have the mounting holes now plated through and connected to ground. We finally were able to get TPS65950 parts, so REV C3 will have those. And we added a few components to add a slight improvement to the S-Video signal.

Gerald