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Intel
®
820E Chipset
R
Design Guide 133
Checklist Items Recommendations Reason/Effect
Cable Detect*
• Host Side/Device Side Detection:
Connect the IDE pin PDIAG/CBLID
to an ICH2 GPIO pin. Connect a
10 k
Ω resistor to GND on the signal
line.
• Device-side detection:
Connect a 0.04 µF capacitor from
the IDE pin PDIAG/CBLID to GND.
No ICH2 connection
The 10 k
Ω resistor to GND prevents GPI
from floating, if no devices are present on
either IDE interface. Allows the use of
3.3 V GPIOs that are not 5 V tolerant.
Note: All ATA66/100 drives can detect
cables.
See Figure 46.
See Figure 47.
Note: The maximum trace length from the ICH2 to the ATA connector is 8 inches.
Table 42. ISA Bridge Checklist
Checklist Items Recommendations Reason/Effect
ICH2 GPO[21] / ISA
NOGO input
Connect ICH2 GPO[21] to ISA NOGO input.
If GPO[21] is not available on the ICH2, any other GPO that defaults
high in the system can be used. GPO[21] is the only ICH2 GPO that
defaults high.
ICH2 AD22 / ISA
IDSEL input
Connect ICH2 AD22 to the ISA IDSEL input.