Intel Pentium 4 User Manual

I/O Controller Hub 2
R
Intel
®
Pentium
®
4 Processor / Intel
®
850 Chipset Family Platform Design Guide 135
9.1.2.1 Combination Host-Side/Device-Side Cable Detection
Host side detection (described in the ATA/ATAPI-4 Standard, Section 5.2.11) requires the use of
two GPI pins (one for each IDE channel). The proper way to connect the PDIAG#/CBLID# signal
of the IDE connector to the host is shown in Figure 87. All IDE devices have a 10 kΩ pull-up
resistor to 5 volts on this signal. Not all of the GPI and GPIO pins on the ICH2 are 5-volt tolerant.
If non 5-volt tolerant inputs are used, a resistor divider is required to prevent 5 volts on the ICH2
or FWH pins. The proper value of the divider resistor is 10 kΩ (as shown in Figure 87).
Figure 87. Combination Host-Side/Device-Side IDE Cable Detection
80-conductor
IDE cable
IDE drive
5 V
ICH2
GPIO
GPIO
Open
IDE drive
5 V
40-conductor
cable
IDE drive
5 V
PDIAG#
ICH2
GPIO
GPIO
IDE drive
5 V
PDIAG#
PDIAG#PDIAG#
10 kΩ
10 kΩ
To secondary
IDE connector
PDIAG#/
CBLID#
PDIAG#/
CBLID#
10 kΩ
10 kΩ
10 kΩ
10 kΩ
IDE_combo_cable_det
Resistor required for
non 5V tolerant GPI
To secondary
IDE connector
Resistor required for
non 5V tolerant GPI
This mechanism allows the BIOS, after diagnostics, to sample PDIAG#/CBLID#. If the signal is
high then there is 40-conductor cable in the system and ATA modes 3, 4, and 5 must not be
enabled.
If PDIAG#/CBLID# is detected low, then there may be an 80-conductor cable in the system, or
there may be a 40-conductor cable and a legacy slave device (Device 1) that does not release the
PDIAG#/CBLID# signal as required by the ATA/ATAPI-4 standard. In this case, BIOS should
check the IDENTIFY DEVICE information in a connected device that supports Ultra DMA modes
higher than 2. If ID Word 93, bit 13 is a 1, then an 80-conductor cable is present. If this bit is 0,
then a legacy slave (Device 1) is preventing proper cable detection, and BIOS should configure the
system as though a 40-conductor cable is present, and notify the user of the problem.

Intel Pentium 4 Specifications

General

Architecture	x86
Core Count	1
Microarchitecture	NetBurst
Manufacturer	Intel
Core Names	Willamette, Northwood, Prescott, Cedar Mill
Virtualization Technology	No
Release Date	November 20, 2000
Clock Speed	1.3 GHz to 3.8 GHz
FSB Speed	400 MHz to 1066 MHz
Socket	Socket 423, Socket 478, LGA 775
Introduced	2000
Product Line	Pentium
Front Side Bus	400 MHz to 1066 MHz
Hyper-Threading	Yes (Prescott and later)
64-bit Support	Yes (Prescott and later)
Instruction Set	MMX, SSE, SSE2, SSE3
Discontinued	2008
Process Technology	180 nm, 130 nm, 90 nm, 65 nm
L2 Cache	256 KB, 512 KB, 1 MB, 2 MB
Lithography	180 nm, 130 nm, 90 nm, 65 nm
L1 Cache	8 KB