14.8.10. Rtc Circuitry; Figure 146. Single Generated Gmch & Ich4-M Vswing/Vref Reference Voltage/ Local Voltage Divider Circuit For Vswing/Vref - Intel 852GM Design Manual

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Figure 146. Single Generated GMCH & ICH4-M VSWING/VREF Reference Voltage/ Local Voltage
Divider Circuit for VSWING/VREF

14.8.10. RTC Circuitry

Pin Name
RTCRST#
CLK_RTCX1,
CLK_RTCX2
CLK_VBIAS
®
Intel 852GM Chipset Platform Design Guide
V
CC
R4
PVSWING
HLVREF
GMCH
R5
C6
C5
System In Series
Pull-up/Pull-down
180 k Ω pull-up to
VccRTC
0.047 µF
HI=1.5V
R6
HI_VSWING
HIREF
R7
C4
C3 C1 C2
RTCRST# requires 18-25 ms delay. Use a 0.1 µF cap
to ground Pull up with 180 k Ω resistor. Any resistor or
capacitor combination that yields a time constant is
acceptable.
Connect a 32.768 kHZ crystal oscillator across these
pins with a 10 M Ω resistor and a decoupling cap at
each signal. Values for C1 and C2 are dependent on
crystal.
See Figure 147.
1 K Ω Connect to CLK_RTCX1 through a 10 M Ω resistor.
Connect to VBATT through a 1 k Ω in series with a
0.047 µF capacitor.
Platform Design Checklist
R4 = 43.2 Ω ± 1%,
R5 = 49.9 Ω ± 1%,
R6 = 78.7 Ω ± 1%,
R7 = 24.2 Ω ± 1%
C1 and C3 = 0.1 µF
(near divider)
C2, C4, C5, C6 =
Intel ®
0.01µF (near
ICH4
component)
Notes
263