W311 Datasheet, PDF (2/19 Pages) Silicon Laboratories – FTG for VIA™ Pro-266 DDR Chipset

W311
Pin Definitions
Pin Name
Pin No.
Pin
Type
Pin Description
RST#
32
O System Reset Output: Open-drain system reset output.
(open-
drain)
CPU1:3
39, 38, 35
O CPU Clock Output: Frequency is set by the FS0:4 input or through serial input interface.
The CPU1:3 outputs are gated by the CLK_STOP# input.
CPU_STOP#
34
I CPU Output Control: 3.3V LVTTL-compatible input that stop CPU1:3.
PCI1:8
10, 11, 13,
14, 16, 17,
18, 20
O PCI Clock Outputs 1 through 8: Frequency is set by FS0:4 inputs or through serial
input interface; see Table 5 for details. PCI1:8 outputs are gated by the PCI_STOP#
input.
PCI_STOP#
33
O PCI_STOP# Input: 3.3V LVTTL-compatible input that stops PCI1:8.
PCI_F
9
O Free-Running PCI Clock Output: Frequency is set by FS0:4 inputs or through serial
input interface; see Table 5 for details.
APIC0:2
45, 44, 42 O APIC Clock Output: APIC clock outputs.
48MHz/FS3
6
I/O 48-MHz Output/Frequency Select 3: 48 MHz is provided in normal operation. In stan-
dard PC systems, this output can be used as the reference for the Universal Serial Bus
host controller. This pin also serves as a power-on strap option to determine device
operating frequency as described in Table 5.
24_48MHz/
FS2
7
I/O 24_48-MHz Output/Frequency Select 2: In standard PC systems, this output can be
used as the clock input for a Super I/O chip. The output frequency is controlled by
Configuration Byte 3 bit[6]. The default output frequency is 24 MHz. This pin also serves
as a power-on strap option to determine device operating frequency as described in
Table 5.
REF1/FS4
47
I/O Reference Clock Output 1/Frequency Select 4: 3.3V 14.318-MHz output clock. This
pin also serves as a power-on strap option to determine device operating frequency as
described in Table 5.
REF0
48
O Reference Clock Output 0: 3.3V 14.318-MHz output clock.
SCLK
28
I Clock pin for SMBus circuitry.
SDATA
29
I/O Data pin for SMBus circuitry.
X1
3
I Crystal Connection or External Reference Frequency Input: This pin has dual func-
tions. It can be used as an external 14.318-MHz crystal connection or as an external
reference frequency input.
X2
4
I Crystal Connection: An input connection for an external 14.318-MHz crystal. If using
an external reference, this pin must be left unconnected.
VDD_REF,
VDD_48MHz,
VDD_PCI,
VDD_AGP,
VDD_CORE
1, 5,15, 24,
31
P Power Connection: Power supply for core logic, PLL circuitry, PCI outputs, reference
outputs, 48-MHz output, and 24_48-MHz output, connect to 3.3V supply.
VDD_CPU,
VDD_APIC
41, 46, 37
P Power Connection: Power supply for APIC and CPU output buffers, connect to 2.5V.
GND_REF,
GND_48MHz,
GND_PCI,
GND_AGP,
GND_CORE,
GND_CPU,
GND_APIC
2, 8, 12, 19,
25, 30, 36,
40, 43
G Ground Connections: Connect all ground pins to the common system ground plane.
2