January 2007 57
Intel
®
855GME Chipset and Intel
®
6300ESB ICH Embedded Platform Design Guide
Intel
®
Pentium
®
M/Celeron
®
M Processor FSB Design and Power Delivery Guidelines
5. Use the Allegro* I (info) command to report the current length of the trace to be equalized.
Record the length in cell B2 of the Excel* spreadsheet.
6. Use the Allegro* “Cut” command to cut the trace in two locations of the serpentine as shown
in Figure 15. This operation generates a floating section of the serpentine.
7. Use the Allegro* “Move ix” (i.e., if vertical routing) command to move the floating section by
the Δ/2 distance listed in cell B4.
8. Reconnect the floating segment if needed.
9. Repeat steps 5 through 8 for the reminder of the traces in the group.
Figure 14. Reference Trace Length Selection
A29#
Reference Length 5950 mil
A[31:17]#
Figure 15. Trace Length Equalization Procedures with Allegro*
Move ix
-
Δ
/2
CUT
Δ = Starting Length – Reference Length
REFERENCE LENGTH
5950
STARTING LENGTH
6012
Δ
-
62
Δ
/
2
-
31
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