Optional Attention Button; Led Indicator Outputs; Hot Plug Interrupt Routing Requirements; Attention Button Implementation - Intel Pentium M Processor Design Manual

8.2.2.2

Optional Attention Button

The Attention Button state is observed on the slot-specific HxPRSNT1# pin. An exclusive-OR
(XOR) gate is inserted between the Slot Present signal and the Hot-Plug controller as shown in
Figure 95. A momentary contact button is connected to the other input of the XOR gate. When the
button is in the released state, the Slot Present signal is unaffected. When the button is actively
being pressed/asserted, the Slot Present signal is inverted, signaling the Hot-Plug controller to
commence slot power up/down sequence.
Figure 95.

Attention Button Implementation

Intel
NOTE: The pin names shown in the Intel
mode, refer to
to
8.2.3

LED Indicator Outputs

The PCI Hot-Plug Standard Usage Model assumes that the platform provides two indicators per
slot. Indicators must be placed in close proximity to their associated slot so that the association
between the indicators and the Hot-Plug slot is clear.
The LED output signals for all modes of the Intel
high. In all cases, the green LED is the power indicator, and the amber LED is the attention
indicator.
8.2.4

Hot Plug Interrupt Routing Requirements

The recommended method to support hot plug is to route the SCI interrupt output signal on the
Intel P64H2 (pin PAIRQ7) to an available GPIO pin on the ICH3. A System Controlled Interrupt
(SCI) is a system interrupt used by hardware to notify the operating system of ACPI events. SCI is
an active-low, shareable, level-triggered interrupt.
Design Guide
®
Intel Pentium
HxSWITCH
®
P64H2
HxPRSNT2#
HxPRSNT1#
Table 76 for the corresponding Intel P64H2 pin name. For dual-slot parallel mode, refer
Table 78 for the corresponding Intel P64H2 pin name.
®
M Processor and Intel
3.3V
MRL Sensor
3.3V
10 kΩ
1 kΩ 5.6 kΩ
XOR
®
P64H2 block are hot-plug slot signal names. For single-slot parallel
®
P64H2 Hot-Plug controller operation are active
®
E7501 Chipset Platform
®
Intel 82870P2 (Intel P64H2)
Slot
330 Ω
3.3V
5.6 kΩ
Slot Present 2
Slot Present 1
Attention
Button
135