Filter
Top Products
Technical Reference Guide
4.5 SYSTEM CLOCK DISTRIBUTION
This system uses clock synthesizers in the IGP and the MCP or MCP-2 components. A 14.31818-
MHz crystal provides an input for clock circuits of the MCP.
Table 4-10 lists clock signals that are distributed between system board components. Frequencies
that are used only internally in chips and components are not listed.
Table 4-10. Clock Generation and Distribution
Table 4-10.
Clock Generation and Distribution
Frequncy Source Destination or Function
266 MHz IGP AGP feedback clock
200 MHz IGP/MCP Hyper Transport Bus clock
133 / 166 MHz [1] IGP Processor, DIMM sockets
66 MHz IGP AGP slot
33 MHz IGP APIC clock
32.768 MHz Crystal MCP, super I/O
25 MHz Crystal NIC PHY
25 MHz NIC PHY MCP
24.576 MHz Crystal Audio codec
16 MHz IGP APIC clock
14.31818 MHz Crystal MCP
14.31818 MHz MCP Clock buffer
14.31818 MHz Clock buffer IGP, super I/O
12.288 MHz Audio codec AC link clock
NOTE:
[1] D315 / d325
These systems uses the spread-spectrum feature of the IGP component. This feature allows BIOS
to set a down spread (0.9 % on the D315, 0.5 % on the d325) to lower the possible effects of high
frequency EMI. Clocks affected by the spread include those used by the processor, memory, and
AGP.
Compaq D315 and hp d325 Personal Computers
Featuring the AMD Athlon XP Processor
Second Edition - April 2003
4-21