Datasheet

Intel® Xeon® Processor D-1500 Product Family and System Clocks
Intel® Xeon® Processor D-1500 Product Family 35
Datasheet - Volume 1 of 4: Integrated Platform Controller Hub
March 2015
2 Intel® Xeon® Processor D-
1500 Product Family and
System Clocks
Intel® Xeon® Processor D-1500 Product Family provides a complete system clocking
solution through Integrated Clocking.
Intel® Xeon® Processor D-1500 Product Family-based platforms require several
single-ended and differential clocks to synchronize signal operation and data
propagation between system-wide interfaces, and across clock domains. In Integrated
Clock mode, all the system clocks will be provided by Intel® Xeon® Processor D-1500
Product Family from a 25 MHz crystal-generated clock input.
The output signals from Intel® Xeon® Processor D-1500 Product Family are:
• One 100 MHz differential source for BCLK (PCI Express* 3.0 jitter tolerant)
• Eight 100 MHz differential sources for PCI Express 2.0 devices
• Two 100 MHz differential source for PCI Express Graphics devices (PCI Express 3.0
jitter tolerant)
• One 100 MHz differential clock for XDP/Intel ITP which can be used as a clock to a
3rd PEG slot (PCI Express 3.0 jitter tolerant)
• Five 33 MHz single-ended source for other devices (One of these is reserved as
loopback clock)
• Four flexible single-ended outputs that can be used for 14.31818/24/33/48 MHz
for legacy platform functions, discrete graphics devices, external USB controllers,
and so on.
2.1 Straps Related to Clock Configuration
Hardware functional straps (that is, pins): None required for clock configuration.
Soft straps implemented in the SPI flash device for Intel® Xeon® Processor D-1500
Product Family clock configuration: Integrated Clocking Profile Select (3 Profile select
bits allow up to 8 different clock profiles to be specified). In addition, 3 RTC well backed
host register bits are also defined for Integrated Clocking Profile Selection through
BIOS.
2.2 SoC Clocking Requirements
Providing a platform-level clocking solution uses multiple system components
including:
•The SoC
• 25 MHz crystal source