RTC section and its working conditions

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gurmeet singh
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RTC section and its working conditions

Post by gurmeet singh »

RTC section and its working conditions .

RTC:

It keeps track on storing the time, date and user’s system settings ,  Even when there is no external power on the board (means the G3 machincal off state)  unless the on board 3.3v coin cell  not removed.

Working and esensital signals of RTC.

1.       VCCRTC .     VccRTC powers PCH RTC well which is mostly connected to the LDO output  3.3v  of 3/5v regulator .which is genraterd before pressing the power button . and a 3.3v internal battery is used for VCCRTC too.  (such as coin cell).

2.       RESET# and SRTCRST#.      These signals are used to clear the system settings or in simple words we can say, to clear cmos settings . these signals are active when low and can b asserted by removing the RTC coin battery or by shorting the cmos clear jumperth.  These signals are also feaded from the same sourceof VCCRTC but through resister dividers to make these signals high and to store system settings.

3.       RTCX1 and RTCX2.      Basicaly ICH/PCH uses a internal timer IC having 256 byte of RAM which keeps track on date, time and system settings.  Ich/pch uses a cristal circuit to genrate a low swing sine wave of 32.768Khz at RTCX1 pin as input to the internal oscillator, and this input signal is amplified and driven back to the cristal circuit through RTCX2 pin of ICH/PCH with the same frequancy of 32.768 Khz but with littel higher amplitude due to amplification . thats why when we check the cristal pins with multimeater we found little diffrence in voltage at both pins. And it is the first check point whther the oscillator circuit of ICH/PCH is initallised or not .

4.       Sus_clock.     The RTCX1 input is amplified for the purpose to drive internal logic of ICH/PCH

And  genrates a free running full swing square wave of same frequancy of 32.768 Khz as

Clock out put for system use . this out put of ICH/PCH is known as SUS_CLOCK.

SUS_CLOCK is the shure short way to check wether the RTC section is working properly or not by checking the wave form.

 

 

Thats why we requires the DSO/CRO to check signals at motherboard as  RTCX1, RTCX2 and SUS_CLOCK have the same  frequancy of 32.768 Khz if we check with frequany meater but the diffrence is the wave form (shape of the wave).

5.       INTRUDER#.  This signals is used through a switch to find out the cover of the system is open or closed . we have seen in some branded systems , COVER OPEN SYSTEM HALT message, which is genrated by this low signal . this signal is also a part of the RTC well. This signal is also kept high through VCCRTC.

6.       INTVRMEN.    ICH/PCH have some internal voltage regulators  and to enable these internal  lenear regulaters an  enable signal is also provided by this RTCVCC as INTVRMEN ( internal regulater enable)

These all signals are the part of RTC WELL and must be present to turn on the board. In the absence of any of these may cause not powering up the board .
Rtc cristal x1 pin .
Pure sine wave of 32khz.
Out put of rtc section to the cristal pin x2 .
Same frequency of 32 khz but diffrence is amplitude . Little high amplitude due to amplification .
Sus_clk output of rtc section . After pressing pwr btn . Full swing squre wave of same 32khz .



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Timothygow
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RTC section and its working conditions

Post by Timothygow »

I dont know whats with that. I downloaded it from that same link today, and it works fine. Whats the exact error message?
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