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Sansa Clip ZIP: Who is the RTC ? :)

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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! 8)
mcc

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