Signal Description
2.12.3
Input Control
The input interface captures eight inputs from each slot. These signals are mapped onto
Intel® 6700PXH 64-bit PCI Hub pins as shown in Table 2-24 and Table 2-25 for serial mode and
Table 2-26 for parallel mode.
• FAULT#: Over-current / Under-volt indication: When asserted, the Intel® 6700PXH 64-bit
PCI Hub, if enabled, immediately asserts reset and disconnects the PCI slot from the bus.
• PRSNT1# and PRSNT2#: Signals which determine whether or not a card is installed to
budget system power. These inputs are connected to the PRSNT1# and PRSNT2# pins on the
PCI card.
• M66EN: Determines if a card is capable of running at 66 MHz in conventional PCI mode.
PRSNT1#
PRSNT2#
Meaning
1
0
1
0
1
1
0
0
No expansion card present
Expansion card present; 25 W maximum
Expansion card present; 15 W maximum
Expansion card present; 7.5 W maximum
• PCIXCAP1 and PCIXCAP2: Determines if a PCI slot is PCI-X capable, and if so, at which
bus frequency it can operate.
PCIXCAP1
PCIXCAP2
Meaning
1
0
1
0
1
1
0
0
100/133 MHz PCI-X Mode
66 MHz PCI-X Mode
Reserved
PCI Mode
• MRL#: Manually operated retention latch sensor input. A logic low input that is connected
directly to the MRL sensor. When asserted it indicates that the MRL latch is closed. If a
platform does not support MRL sensors, this must be wired to a low logic level (MRL closed).
• ATTENTION BUTTON#: Signal connected to the PCI slot’s attention button. When low,
indicates that the operator has requested attention. If an attention button is not implemented,
then this input must be wired to a high logic level.
2.12.4
Serial Mode Operation
During Serial mode operation, the Intel® 6700PXH 64-bit PCI Hub sends and receives information
serially from the slot control logic. The slot control logic is required to deserialize the output
information to the bus switches and slot. The Slot control logic is also required to convert parallel
input information from the slots into serial data to the Intel® 6700PXH 64-bit PCI Hub. The serial
interface will run at 16.5 MHz. In this mode, the Intel® 6700PXH 64-bit PCI Hub constantly polls
the slot inputs, serially looking for an event at any of the hot plug slots. The output serial stream
from the Intel® 6700PXH 64-bit PCI Hub is on-demand and is only sent when the
Intel® 6700PXH 64-bit PCI Hub needs to schedule an event at a slot.
Intel® 6700PXH 64-bit PCI Hub Datasheet
49
INTEL [ INTEL ]
