Sansa Clip ZIP: Who is the RTC ? :)

[mcc01]

Hi,

Since even the FM radiochip (SI4703) delivers a clock of 32765 ticks...
What chip does the timekeeping inside the Sansa Clip ZIP?

Thank you very much in advance for any help!
Best regards,
mcc

[saratoga]

There are several dedicated timers on the AMS chip that provide time keeping. 

[mcc01]

Hi Saratoga,

thank you for your infos!

ooops...sorry.
I didn't specify, what the intention was for my question...

Two kinds of "time sources" I am interested in:
1.) Which "chip" (or """entity""") is responisble for keeping the
     wall clock time. Or the other way aorund: If I set time and date:
     Which hardware do I influence then?
2.) If I set a sleep timer and/or a wake-up-timer: What hardware
     is influenced by this action?

Another question of this topic:
Is there a hardware restricting to limit alarm- or wake-up-timer-settings
to five minutes ?

Thank you very much for help in advance!
Best regards
mcc

[saratoga]

1)  The timers (and virtually everything else but the radio and flash memory) are on the main SOC. 

2)  IIRC you are basically setting the real-time clock to generate an interrupt when the clock reaches a certain value (sleep timer) or to power on the device (wake timer).   

3)  No, the actual resolution is probably 10s to 100s of microseconds.

[mcc01]

Hi Saratoga,

thank you ! That helps!

Main SoC: I check the rockbox.org-site for information about the SoC
for downlaoding the correct datasheets.
I am a little confused about the informations I found:
Checking the compilation results of rockbox I found that
./firmware/drivers/rtc/rtc_as3514.o is compiled.
Than I found, the SoC of the Sansa Clip ZIP is a
AS3525 -- but the "v2" version which is not a AS3525
but a "rockbox internal only" nameing...and seomwhere
I found, that all that ha something to do with a AS3514
and a AS3543...somehow.
I dont know when these information were written into
the webpages (the Sansa Clip ZIP is of Nov 2011 as far
as I know) and wether they were updated, if new information
were available.
Summa summarum: Which datasheets do I need to "understand"
hardware of my Sansa Clip ZIP and program on/for it in a
non-frustrating and non-harmful (for the hardware) way?

Thank you very much for any help and the your understanding
for a bloody newbie in advance!
Best regards and have a nice weekend!
mcc

[saratoga]

There is no datasheet for the SOC used in the Zip, however for many things, the AS3525 will be close.  If in doubt, look at the source code. 

The AS3543 closely matches the DAC used in the AS3525v2, so that is sometimes referenced. 

[mcc01]

Hi Saratoga,

thanks for view inside...

There is no datasheet for the SOC used in the Zip

...at least is it known, what the exact name of that SOC is?

Best regars,
mcc

[saratoga]

...at least is it known, what the exact name of that SOC is?

I don't think it has a name.