Intel 21555 Benutzerhandbuch
21555 PCI-to-PCI Bridge Evaluation Board User’s Guide
11
Introduction
1.6.1
Clock Configuration
describes the resistor jumpers to install that connect p_clk and s_clk_o to the Mictor
connectors. To improve signal integrity and minimize noise, these signals are not wired to the
Mictor connectors. Resistor jumpers also control the selection of clock signals. See
Mictor connectors. Resistor jumpers also control the selection of clock signals. See
for the resistor jumper locations. See
for Mictor pinouts.
1.6.2
Clamping Voltage
gives the clamping voltage resistor jumper configurations. These jumper resistors
designate the DE1B55503 as a 3.3V or a 5V PCI device. A mix of 3.3 and 5 V cards is not allowed.
The E1 regulator provides the 3.3V or 5 V clamping voltage for the local bus. The resistor jumpers
connect s_vio to either 3.3V or 5V.
The E1 regulator provides the 3.3V or 5 V clamping voltage for the local bus. The resistor jumpers
connect s_vio to either 3.3V or 5V.
shows the location of the resistor jumpers.
Table 3. Clock Configuration Jumpers
Clock Source
Installed
Removed
Use the s_clk_o signal from the 21555 as the local
clock.
clock.
R65, R73
R68, R93
Use the s_clk_i that is the output of the clock buffer
as the local clock.
as the local clock.
R73
R68
Use the system slot to drive the 21555 s_clk_i.
R68
R73
Use an oscillator as the asynchronous local clock.
R93
R65, R68
Use the system slot to provide the local clock.
R92, R116, R69
R91, R115, R72
Use the clock buffer to provide the local clock.
R91, R115, R72
R92, R116, R69
Table 4. Voltage Clamp
a
a.
Only one jumper resistor (R95 or R97) may be installed at
a time. Installing both or no jumper resistors is not allowed.
a time. Installing both or no jumper resistors is not allowed.
Function
Installed
Removed
s_vio is 3.3V
R95
R97
s_vio is 5V
R97
R95