Geode NX, Bridge configurations

The following reports are applicable in Geode NX and Athlon XP-M.
The content of this page is not necessarily certain. Please confirm it by yourself.

Function of the bridges for the Mobile CPUs.

CPU Bridge number

• L1 : It is connected from L3 to BP_FID pin.
• L2,L9 : Level2 Cache controls
• L3 : Start up Multipliers
• L5 : Operation mode of CPU
• L6 : SFID, Rated Multiplier for Mobile
• L8 : SVID, Maximum Core voltage for Mobile
• L11 : VID, Start up Core voltage
• L12 : FSB auto-detection
• Summary : About closing of the bridges

About the CPU Bridges

The allocation and the function of the bridge identification number are due to our presumption. They are not being written in the data sheet.

L1 : It is connected from L3 to BP_FID pin.

There is no problem in L1. Please leave just as it is.

Geode NX and Athlon XP-M can still change the start up multiplier. However, present Athlon XP and Sempron are locked to the ratings multiplier regardless of the state of L1.

L2 : Level2 Cache controls

There is no problem in L2 and L9. Please leave just as it is.

L2 bridge is a setting concerning the Level2 cache. And, all states of default are closed, and it is the maximum value.

L2Bridges

OPN	L2[3:0]	L2 Cache	Products
ANXS1750FXC3S	CCCC	256k	Geode NX (T-bred)
AXMH2200FQQ3C	CCCC	256k	XP-M (T-bred)
AXMG2600FQQ4C	CCCC	512k	XP-M (Barton)

T-bred* = Thoroughbred

L3 : Start up Multipliers

The L3 bridges are the starting multipliers. The reason that starts by 6X or 5X is in this bridge.

If the mother board doesn't have the multiplier changeing function, it is possible to change the multiplier by the L3[4:0] Bridges.

Startup Multiplier

OPN	L3[4:0]	Multiplier	Products
ANXS1750FXC3S	CC::C	6X	Geode NX 1750
ANXL1500FGC3S	CC::C	6X	Geode NX 1500
ANXL1250FYC3S	CC:CC	5X	Geode NX 1250
AXMH2200FQQ3C	CC::C	6X	Athlon XP-M 2200
AXMS1600FWS3B	CC:CC	5X	Athlon XP-M 1600

However, we know better techniques more than the processing of the bridges. Please refer to the following.
refs: Multiplier on the fly

L3 Bridges

Start up Multipliers are as follows.

Mul	Frequency (FSB133)	L3-FID [4:0]	M_133#
13.0x	1.73G	:C:CC	XP 2100+
13.5x	1.80G	:C:C:	XP 2200+
14.0x	1.87G	:C::C	-
21.0x	-	:C:::	-
15.0x	2.00G	::CCC	XP 2400+
22.0x	-	::CC:	-
16.0x	2.13G	::C:C	-
16.5x	2.20G	::C::	-
17.0x	2.27G	:::CC	-
18.0x	2.40G	:::C:	-
23.0x	-	::::C	-
24.0x	-	:::::	-
n/a	x	:CCCC	x
19.0x	-	:CCC:	-
n/a	x	:CC:C	x
20.0x	-	:CC::	-

C=closed ( Logic 0 ), : =open ( Logic1 )
Mobile*1 : NX1250, and the product of Mobile version with 100MHz FSB.
Mobile*2 : In general, the product of Mobile version with 133MHz FSB.
n/a : non available

Geode NX and Athlon XP-M can still change start up Multiplier by L3. If it is possible, we will recommend the Multiplier change circuit to be installed. Please refer to Barton /Multiplier circuit

L5 : Operation mode of CPU

Recognition which product it is changes with this bridge. It might have to be called product ID.

L5

L5 [ 3 ] closed : Multiprocessing Capable
L5 [ 2 ] closed : Mobile-mode
L5 [ 1 ] opened : default ( Valid L6 value )
L5 [ 0 ] closed : default ( Valid L8 value )

If L5 [ 1 ] is opened, the ratings multiplier becomes 24X.

Operation mode of CPU

OPN	L5				Brand	Notes
	[3]	[2]	[1]	[0]
ANXS1750FXC3S	C	C	:	C	Geode NX	NX 1750 (T-bred)
ANXL1500FGC3S						NX 1500 (T-bred)
AXMS1400FWS3B	C	C	:	C	Athlon XP-M	XP-M 1400+ (T-bred)
AMSN2200DKT3C	C	:	:	C	Athlon MP	MP 2200+ (T-bred)
SDA2400DUT3D	C	:	:	C	Sempron	Sempron 2400+ (T-bred)
AXDA1700DLT3C	:	:	:	C	Athlon XP	XP 1700+ (T-bred)

It is understood that Geode NX is the same setting as Athlon XP-M.

L6 : SFID | Rated Multiplier for Mobile

The L6 bridge is FID only for mobile CPUs. The Multiplier of ratings is set in Geode NX and Athlon XP-M. This bridge is used as a limit value when it starts changing the Multiplier from software.

Cancellation of L6 multiplier
To set Multiplie in 24X of the maximum value, it only has to close L5 1. However, there are a possibility of many of boards equipped with AMI BIOS that your PC cannot be started.

Mul	Frequency		L6[4:0]	Model#
	FSB133	FSB167
13.0x	1733	2167	:C:CC	-
13.5x	1800	2250	:C:C:	AXMH2400FQQ4C
14.0x	1867	2333	:C::C	AXMH2500FQQ4C
21.0x	-	-	:C:::	-
15.0x	2000	2500	::CCC	AXMG2600FQQ4C
22.0x	-	-	::CC:	-
16.0x	2133	2667	::C:C	-
16.5x	2200	2750	::C::	-
17.0x	2267	2833	:::CC	-
18.0x	2400	3000	:::C:	-
23.0x	-	-	::::C	-
24.0x	-	-	:::::	-
3.0x	400	500	:CCCC	n/a
19.0x	-	-	:CCC:	-
4.0x	533	667	:CC:C	n/a
20.0x	-	-	:CC::	-

The column of FSB 333 is a reference value. It is not ratings.

Attention with AMI BIOS

In Geode NX and Athlon XP-M, many of boards equipped with AMI BIOS start by ratings Multiplier. In this case, BIOS refers to this L6 bridge. And, it seems to set Multiplier to ratings again immediately after the start. For the mother of this type, we will recommend the Multiplier change by CrystalCPUID.

L6 are all closed in CPU of a desktop version because it is not used.

L8 : SVID | Maximum Core voltage for Mobile

In Geode NX and Athlon XP-M, L8 bridges are the same settings as L11 bridges. However, anything doesn't change even when this bridge is changed.

In the system for mobility, not only VID but also the SVID pin output is used to set the voltage. The L8 bridge seems to be used to acquire the rated voltage at this time, and to be set the maximum value of SVID.

L11 : VID | Startup Core voltage

The default core voltage is set to L11. It becomes 1.425V in automatic recognition though the rated voltage of Geode NX 1750 is 1.25V. However, it becomes 1.25V of ratings in laptop PC.

Athlon VID Code 2

V_CORE (V)		VID
Mobile	Desktop	[4:0]
Geode NX Athlon XP-M	-	L11
1.275	1.450	:CCCC
1.250(X)	1.425	:CCC:
1.225	1.400	:CC:C
1.200(T)	1.375	:CC::
1.175	1.350	:C:CC
1.150(C)	1.325	:C:C:
1.125	1.300	:C::C
1.100(Y)	1.275	:C:::
1.075	1.250	::CCC
1.050	1.225	::CC:
1.025	1.200	::C:C
1.000(G)	1.175	::C::
0.975	1.150	:::CC
0.950	1.125	:::C:
0.925	1.100	::::C
-	-	:::::

C shows bridge closed. Logic is 0.
: shows bridge opend. Logic is 1.

L12 : FSB | FSB setting auto-detection

In general, you may disregard this bridge. However, L12 seems to be used for FSB automatic recognition in some of mother boards. ( Example, GIGABYTE GA-7VAXP Ultra etc )

L12 [3] : closed
L12 [2] : FSB_Sense[1]
L12 [1] : closed
L12 [0] : FSB_Sense[0]

L12 FSB_Sense[1:0]

OPN	L12[2]	L12[0]	FSB	Notes
AXMD1600FQQ3B	:	:	100 MHz	XP-M (T-bred)
AXDA1700DLT3C	:	:	133 MHz	XP (T-bred)
AXDC2400DKV3C				XP (Thorton)
ANXS1750FXC3S	:	C	133 MHz	Geode NX (T-bred)
ANXL1500FGC3S
AXMH2000FLQ3C	:	C	133 MHz	XP-M (T-bred)
AXMH2500FQQ4C				XP-M (Barton)
AXDA2500DKV4D	C	:	167 MHz	XP (Barton)
AXDA3200DKV4E	C	C	200 MHz	XP (Barton)

: = open (logic level of 1) C = closed (logic level of 0)

attention : About closing of the bridges

Fundamentally, since processing of the bridge is dangerous, we cannot recommend you.
However, when you need processing of the bridges, be careful of below.

How to set the bridge of [Open] to [Close]

It is made to [Close] by using the electric conductive material.
We know the Laser pit should be filled with an insulator before anything else. In a present CPU package, it might be difficult to connect two points in the bridge. In this case, it can be solved by filling the laser pit directly with the electric conductive material.

How to set the bridge of [Close] to [Open]

The bridge is set to [Open] by cutting carefully with an edged tool.

L bridges			Geode NX, Method of closing the bridges
L#	Function	Impedance to GND	Insulation + closing	Closing Directly	Notes
L1	It is connected from L3 to BP_FID pin.	Insulated	-	-	Please maintain this state.
L2	Level2 Cache controls	1k Ohm	-	-	Please maintain this state.
L3	Start up Multipliers	1k Ohm	Best (Difficult)	Good (see notes)	notes : It becomes impossible to use the multiplier change function of the motherboard.
L5	Operation mode of CPU	0 Ohm	-	Optimal	No problem
L6	SFID, Rated Multiplier for Mobile	0 Ohm	-	Optimal	Only in Mobile CPUs
L8	SVID, Maximum Core voltage for Mobile	0 Ohm	-	Optimal	Only in Mobile CPUs
L9	It is connected from L2 to L2_control pin	Insulated	Unnecessary	No Good	There is no advantage usually.
L11	VID, Startup Core voltage	0 Ohm	-	Optimal	No problem
L12	FSB auto-detection	1k Ohm	Best (Difficult)	Good (see notes)	notes : It is unnecessary in a lot of mother boards.

• Created on 04/17/2005