........................Document #: 38-07519 Rev. ** Page 2 of 21
Pin Description
Pin # Name Type Description
3X1 ICrystal Connection or External Reference Frequency Input: This
pin has dual functions. It can be used as an external 14.318-MHz
crystal connection or as an external reference frequency input.
4X2 OCrystal Connection: Connection for an external 14.318-MHz crystal.
If using an external reference, this pin must be left unconnected.
48 REF0/MULTSEL0 I/O Reference Clock 0/Current Multiplier Selection 0: 3.3V 14.318-MHz
clock output. This pin also serves as a power-on strap option to
determine the current multiplier for the CPU clock outputs. The
MULTSEL1:0 definitions are as follows:
MULTSEL1:0
00 = Ioh is 4 x IREF
01 = Ioh is 5 x IREF
10 = Ioh is 6 x IREF
11 = Ioh is 7 x IREF
150k internal pull down.
1 REF1/MULTSEL1 I/O Reference Clock 1/Current Multiplier Selection 1: 3.3V 14.318-MHz
clock output. This pin also serves as a power-on strap option to
determine the current multiplier for the CPU clock outputs. The
MULTSEL1:0 definitions are as follows:
MULTSEL1:0
00 = Ioh is 4 x IREF
01 = Ioh is 5 x IREF
10 = Ioh is 6 x IREF
11 = Ioh is 7 x IREF
150k internal pull up.
41, 38, 40, 37 CPUT(0:1),
CPUC(0:1)
O CPU Clock Outputs: Frequency is set by the FS0:4 inputs or through
serial input interface.
44, 45 CPU_ITP,
CPU_ITP#
O CPU Clock Output for ITP: Frequency is set by the FS0:4 inputs or
through serial input interface.
31, 30, 28 3V66_0:2 O 66MHz Clock Outputs: 3.3V fixed 66-MHz clock.
6 PCI_F0/FS2 I/O Free-running PCI Output 0/Frequency Select 2: 3.3V free-running
PCI output. This pin also serves as a power-on strap option to
determine device operating frequency as described in the Frequency
Selection Table. 150k internal pull up.
7 PCI_F1/FS3 I/O Free-running PCI Output 1/Frequency Select 3: 3.3V free-running
PCI output. This pin also serves as a power-on strap option to
determine device operating frequency as described in the Table 2.
150k internal pull up.
8PCI_F2OFree-running PCI Output 2: 3.3V free-running PCI output.
10 PCI0/FS4 I/O PCI Output 0/Frequency Select 4: 3.3V PCI output. This pin also
serves as a power-on strap option to determine device operating
frequency as described in Table 2. 150k internal pull up.
11, 12, 14, 15, 16,
17
PCI(1:6) O PCI Clock Output 1 to 6: 3.3V PCI clock outputs.
22 48MHz_0/FS0 I/O 48MHz Output/Frequency Select 0: 3.3V fixed 48-MHz, non-spread
spectrum output. This pin also serves as a power-on strap option to
determine device operating frequency as described in Table 2.
This output will be used as the reference clock for USB host controller
in Intel 845 (Brookdale) platforms. For Intel Brookdale – G platforms,
this output will be used as the VCH reference clock. 150k internal pull
up.
