I propose that the traces on Chehalis be categorized into five
classes:
1. High-speed differential pairs
	These signals should be routed on a single layer without any
	vias (except at the ends), with extra care that all discontinuities
	are symmetrical between the two traces. Must be adjacent to a
	ground plane with no breaks, and no parallel traces are allowed
	on the adjacent trace layer. Use 4 mil traces with 8 mils
	between the edges (12 mils center to center).
	Minimum spacing between pairs going in the same direction 12 mils.
	All routing on layers 4 and 11.
	Could use 6-mil edge to edge if it's too crowded.
	(8 mil e-e is 88/93 ohms, 6 mil e-e is 85/90 ohms)
	______________________________________
          ____    ____        ____    ____

	______________________________________ <== layer empty!
2. Differential pairs that can tolerate more crosstalk
	Relaxed rules from class 1.
	Pairs run on adjacent layers, with the two traces of a pair
        immediately over each other. Spacing between pairs as
	small as 6 mils. Vias allowed, but watch trace lengths,
	and keep them equal. Spacing to non-differential traces
	minimum 8 mils.
	______________________________________
	    ____      ____      ____      ____
	    ____      ____      ____      ____
	______________________________________

3. Single-ended traces that must function at high data rates
	A particular trace can go on layers 2-4, 5-7, 8-10, or 11-13.
	In other words, a trace which starts adjacent to a particular
	plane should be routed next to that plane the entire distance,
	either above the plane or below the plane.  Thus, a trace that
	starts at layer 5 may only be on layers 5 and 7.
	May not cross a break in the underlaying plane.
	4 mil traces. What about crosstalk?
4. Single-ended traces that are still important, but slower
	As above, but relaxed. Allow routing over plane breaks?
	Allow arbitrary plane jumps?
5. Don't care traces: static signals, LEDs, etc.
	Route anywhere, any way you can!

A beginning of categorizing these traces follows:

---------------------------------------------------------------------------
Class 1

Pages	Names
1,4	FS_XP(28) <=> FS_XN(28)		Feldspar data clock 190M
1,4	FS_YP(28) <=> FS_YN(28)		Feldspar data clock 190M
3	FTA_RDP <=> FTA_RDN		Fiber-optic signal 2.5G
3	FTB_RDP <=> FTB_RDN		Fiber-optic signal 2.5G
3	FTA_TDP <=> FTA_TDN		Fiber-optic signal 2.5G
3	FTB_TDP <=> FTB_TDN		Fiber-optic signal 2.5G
3	CLK125P <=> CLK125N		125M Clock
9,10	CLK00 <=> CLK00N		ADC Reference 95M
9,10	CLK01 <=> CLK01N		ADC Reference 95M
10	U148-7 <=> U148-8		Reference feedback 95M
10	VCO_OUTN <=> VCO_OUTP		Reference feedback 95M
10,11	REF <=> REFN			Board Reference 10M/5M
10,11	CLK04 <=> CLK04N		Board Reference 5M
---------------------------------------------------------------------------
Class 2

Pages	Names
1,4	FS_XP(27:0) <=> FS_XN(27:0)	Feldspar data
1,4	FS_YP(27:0) <=> FS_YN(27:0)	Feldspar data
1,5	DDCK0 <=> DDCK0*		DRAM clock
1,5	DDCK1 <=> DDCK1*		DRAM clock
3	J4-A2  <=> J4-A3		PCIe
3	J4-A5  <=> J4-A6		PCIe
3	J4-A8  <=> J4-A9		PCIe
3	J4-A11 <=> J4-A12		PCIe
3	J4-A14 <=> J4-A15		PCIe
3	J4-B2  <=> J4-B3		PCIe
3	J4-B5  <=> J4-B6		PCIe
3	J4-B8  <=> J4-B9		PCIe
3	J4-B11 <=> J4-B12		PCIe
3,9	ADCSP0 <=> ADCSN0		ADC Data 950M
3,9	ADCSP1 <=> ADCSN1		ADC Data 950M
3,9	ADCSP2 <=> ADCSN2		ADC Data 950M
3,9	ADCSP3 <=> ADCSN3		ADC Data 950M
3	ADCSP0C <=> ADCSN0C		ADC Data 950M
3	ADCSP1C <=> ADCSN1C		ADC Data 950M
3	ADCSP2C <=> ADCSN2C		ADC Data 950M
3	ADCSP3C <=> ADCSN3C		ADC Data 950M
10	C1367-1 <=> C1367-2
1,10	VCXO_VP <=> VCXO_VN		VCO voltage divider output
10	VCXO_VPR <=> VCXO_VNR		VCO voltage divider output
---------------------------------------------------------------------------
Class 3

Pages	Names
	ADC_SYNC
	ADC_TRIGA
	ADC_TRIGB
	DDA(13:0)
	DDBA(2:0)
	DDCAS*
	DDCKE0
	DDCKE1
	DDDQ(63:0)
	DDDQS(7:0)
	DDODT0
	DDRAS*
	DDS0*
	DDS1*
	DDWE*
	FS_CLK95
---------------------------------------------------------------------------
Class 4
	ADC_ACLKP
	ADC_BCLKP
	BVA(15:1)
	BVAM(5:0)
	BVAS*
	BVD(31:0)
	BVDS0*
	BVDS1*
	BVLWORD*
	BVMODID
	BVWRITE*
	CD_CS*
	CD_SCLK
	CD_SDI
	CD_SDO
	FLA(20:0)
	FLCE
	FLD(15:0)
	FLOE
	FLWE
	FPGA_5MHZ_IN
	FPGA_5MHZ_OUT
	FS_CDAV
	FS_CRFD
	FS_PDAV
	FS_SFLD
	FS_STAT(3:0)
	FS_TCK
	SCL
	SDA
	SSAB_DAT
	SSA_CLK
	SSA_DAT3
	SSA_DATR
	SSA_STB
	SSB_CLK
	SSB_DAT3
	SSB_DATR
	SSB_STB
	SSC_CLK
	SSC_DAT
	SSC_DATR
	SSC_STB
	SYNC_IN
	SYNC_OUT
	TRIG_IN
	VBERR*
	VBERRO
	VBUF_DIR_IN
	VD(31:0)
	VDTACK*
	VDTACKO
---------------------------------------------------------------------------
Class 5
	ADDCA_DITH
	ADDCA_PGA
	ADDCA_RAND
	ADDCA_SHDN
	ADDCA_SHDN*
	ADDCB_DITH
	ADDCB_PGA
	ADDCB_RAND
	ADDCB_SHDN
	ADDCB_SHDN*
	ATTEN02CHA*
	ATTEN02CHB*
	A_OVERLOAD
	B_OVERLOAD
	DDODT1
	DEBUG(15:0)
	DEBUGCLK
	FA_RX
	FA_TX
	FB_RX
	FB_TX
	FS_LOCK(1:0)
	FS_PRST
	FS_RST
	FS_TDI
	FS_TDO
	FS_TDO2
	FS_TDO3
	FS_TMS
	FS_TRST
	FTA_SIGDET
	FTA_TXDIS
	FTB_SIGDET
	FTB_TXDIS
	IFBLKCHA
	IFBLKCHB
	IFGAIN16CHA
	IFGAIN16CHB
	IFGAIN8CHA
	IFGAIN8CHB
	IFSELCHA
	IFSELCHB
	LADDSW(7:0)
	LED2
	PCIRST
	RESET*
	V_ACCESS
	---------------------------------------------------------------------------


(From Howard Johnson)
 Below   I   have  attached  a  listing  of   100-ohm
   stripline configurations. Obviously, this is just  a
   small sampling of all possible combinations. In  the
   chart,  dimension "b" is the interplane  separation,
   "h"  the  height  of  the trace  above  the  nearest
   plane,  "w"  the trace width, and "s"  the  edge-to-
   edge  separation,  all in mils. Parameter  rSKIN  is
   the  effective AC skin-effect resistance at  1  GHz,
   Z0  is  the (high-frequency value of) characteristic
   impedance, and the column marked "dB/in.  @1GHz"  is
   the  trace  attenuation due to the skin  effect,  in
   dB/in.,  at  a frequency of 1 GHz. Don't  forget  to
   also  consider dielectric losses. All the  stripline
   configurations  assume  1/2-oz  Copper  on  an  FR-4
   substrate with Er=4.3 at 1GHz.
   
   I hope this information is useful to you.
   

Best Regards,
Dr. Howard Johnson

   100-OHM DIFFERENTIAL STRIPLINE DIMENSIONS
   (    All at Er=4.3. 1/2-oz Cu.)
   
b     h     w     s     rSKIN     Z0     (dB/in.@1GHz)
10     3     3     40     3.501      99.03    0.1522
10     4     3     7      3.235     100.4     0.1389
10     5     3     7      3.218     101.2     0.1371
10     5     4     40     2.76       94.59    0.1258
14     4     3     5.5    3.191     101       0.1361
14     4     4     12     2.738     100.3     0.1177
14     5     3     4.5    3.136     100.1     0.135
14     5     4     7.5    2.599     100.5     0.1116
14     5     5     40     2.329     99.51     0.1011
14     7     3     4.5    3.112     101.8     0.1317
14     7     4     6.5    2.556     100.6     0.1096
14     7     5     13     2.236     100.9     0.09574
14     7     6     40     2.006      94.98    0.09126
20     5     3     4.4    3.141     101       0.134
20     5     4     6.5    2.592     100.7     0.1111
20     5     5     11     2.271     100.6     0.09746
20     5     6     40     2.087      98.41    0.0916
20     7     3     3.9    3.132     101.1     0.1336
20     7     4     5.2    2.547     100.9     0.1089
20     7     5     7      2.165     100.7     0.0929
20     7     6     10     1.908     100.3     0.08218
20     7     7     19     1.75      100.7     0.0751
20     7     8     40     1.613      96.34    0.07242
20     10    3     3.7    3.143     100.6     0.1347
20     10    4     5      2.54      101.6     0.1079
20     10    5     6.5    2.148     101.4     0.0915
20     10    6     8.5    1.876     100.7     0.08054
20     10    7     12     1.682     100.5     0.07236
20     10    8     25     1.562     100.3     0.06735
30     5     3     4.3    3.147     100.7     0.1347
30     5     4     6.3    2.595     100.7     0.1112
30     5     5     10     2.268     100.7     0.09729
30     5     6     22     2.087     100.2     0.08996
30     6     3     4      3.139     101       0.1339
30     6     4     5.4    2.564     100.7     0.1099
30     6     5     7.5    2.195     100.7     0.09415
30     6     6     11.2   1.955     100.6     0.08399
30     6     7     20     1.81      100.4     0.07795

*-----------------------------------------------------*
