[P2B-D] -- question about connections
 

hello,

after some summer break I come back to the idea of modding my old p2b-d.
I reviewed the document here http://tipperlinne.com/p2b-ds150.htm and
want to make myself sure wheater the connections between pins are as
follows:

http://www.geocities.com/qroobas/ds-before.jpg

I would use 2-pin FS3 instead of 3-pin if the third pin, the rightmost
one, is unused. I would appreciate confirmation of these connections by
the author or Paul or somebody, who has done such modification.

thanks,
geos

geos wrote:
hello,

after some summer break I come back to the idea of modding my old p2b-d.
I reviewed the document here http://tipperlinne.com/p2b-ds150.htm and
want to make myself sure wheater the connections between pins are as
follows:

http://www.geocities.com/qroobas/ds-before.jpg

No, that's incorrect.

The leftmost pin (1) on all FSx jumpers is connected to Vio (3.3v) and
the rightmost pin (3) to ground. The middle pin (2) is connected to the
corresponding FSx input of the clock generator chip via a 10K ohm
resistor, so you get a logic '1' applied to the clock generator's FSx
pin when the jumper is set 1 - 2 and logic '0' when the jumper is set 2
- 3.

I would use 2-pin FS3 instead of 3-pin if the third pin, the rightmost
one, is unused. I would appreciate confirmation of these connections by
the author or Paul or somebody, who has done such modification.

thanks,
geos

The clock generator has an internal pull-down resistor to ground on FS3
(unlike FS[0-2], which have an internal pull-up), so a 2-pin jumper
(pins 1 & 2 only) will work, but it leaves the 10K ohm programming
resistor and attached wire floating when the jumper is removed - which
could theoretically introduce noise on the PCI clock signal. Note that
FS3 changes function from an input during reset to a clock output during
operation.

I follow the clock generator chip manufacturer's recommendation and
install a 3-pin FS3 jumper.

P2B

In article , geos wrote:

hello,

after some summer break I come back to the idea of modding my old p2b-d.
I reviewed the document here http://tipperlinne.com/p2b-ds150.htm and
want to make myself sure wheater the connections between pins are as
follows:

http://www.geocities.com/qroobas/ds-before.jpg

I would use 2-pin FS3 instead of 3-pin if the third pin, the rightmost
one, is unused. I would appreciate confirmation of these connections by
the author or Paul or somebody, who has done such modification.

thanks,
geos

This is my previous post:

http://groups.google.com/groups?selm...0192.168.1.177

This is a schematic diagram of the wiring.

+3.3V
+3.3V ---X |
10K |
X----/\/\/\---+ \ (Internal
"strap" | / 240K
GND ---X | \ Pullup
------------- | / Resistor)
| | |
| | | 22 ohm
PCICLK0 |----+--+--/\/\/\--------- Clock to PCI slot
| Series
| Damping
------------- Resistor ("R99")

Now, we redraw it physically:

+-------------------------------------
| |
| |
10K ----------- | New
Resistor | | X X X FS3
| | 9250 | | |
------R99---+-------Pin9| Clock | | |
22ohm PCICLK0| Gen | +----+ |
| | | +----+
----------- | |
X X X FS0
X X X FS1
X X X FS2
(+3.3) (GND)

All three pins of the new header are used. The end pins of FS3
are feeding from the end pins of FS0. All the left hand side
FS pins are at 3.3V, and the right hand ones are at GND potential.
The long wire goes from the center pin of FS3, to the end of the
new 10K ohm resistor. The other end of the 10K ohm resistor is
soldered to the junction of R99 (where the right hand side of
R99 is soldered to its pad). This keeps the bottom end of the
10K resistor close to the circuit, keeping the stub length down.
The wire going from the top of the 10K resistor isn't critical, so it
doesn't have to be strung like a guitar string. Neither are the
two wires running from the left and right header pins of FS3,
when they connect to the left and right header pins on FS0.

The photograph from Tipperlinne is deceptive and the photo should
have been taken before the hot glue was added, or at least the
solder joints should have been visible.

HTH,
Paul

Paul wrote:

In article , geos wrote:


hello,

after some summer break I come back to the idea of modding my old p2b-d.
I reviewed the document here http://tipperlinne.com/p2b-ds150.htm and
want to make myself sure wheater the connections between pins are as
follows:

http://www.geocities.com/qroobas/ds-before.jpg

I would use 2-pin FS3 instead of 3-pin if the third pin, the rightmost
one, is unused. I would appreciate confirmation of these connections by
the author or Paul or somebody, who has done such modification.

thanks,
geos


This is my previous post:

http://groups.google.com/groups?selm...0192.168.1.177

This is a schematic diagram of the wiring.

+3.3V
+3.3V ---X |
10K |
X----/\/\/\---+ \ (Internal
"strap" | / 240K
GND ---X | \ Pullup
------------- | / Resistor)
| | |
| | | 22 ohm
PCICLK0 |----+--+--/\/\/\--------- Clock to PCI slot
| Series
| Damping
------------- Resistor ("R99")


The internal resistor is actually a pull-down - that's why FS3 defaults
to logic 0 when FS3 is omitted entirely (i.e. as shipped by Asus).

Now, we redraw it physically:

+-------------------------------------
| |
| |
10K ----------- | New
Resistor | | X X X FS3
| | 9250 | | |
------R99---+-------Pin9| Clock | | |
22ohm PCICLK0| Gen | +----+ |
| | | +----+
----------- | |
X X X FS0
X X X FS1
X X X FS2
(+3.3) (GND)

All three pins of the new header are used. The end pins of FS3
are feeding from the end pins of FS0. All the left hand side
FS pins are at 3.3V, and the right hand ones are at GND potential.
The long wire goes from the center pin of FS3, to the end of the
new 10K ohm resistor. The other end of the 10K ohm resistor is
soldered to the junction of R99 (where the right hand side of
R99 is soldered to its pad). This keeps the bottom end of the
10K resistor close to the circuit, keeping the stub length down.
The wire going from the top of the 10K resistor isn't critical, so it
doesn't have to be strung like a guitar string. Neither are the
two wires running from the left and right header pins of FS3,
when they connect to the left and right header pins on FS0.

The photograph from Tipperlinne is deceptive and the photo should
have been taken before the hot glue was added, or at least the
solder joints should have been visible.

Fair comment - I'll try to get a better picture next time I do one.

HTH,
Paul

In article , P2B
wrote:

snip

The photograph from Tipperlinne is deceptive and the photo should
have been taken before the hot glue was added, or at least the
solder joints should have been visible.

Fair comment - I'll try to get a better picture next time I do one.

HTH,
Paul

It is difficult to keep everyone happy when doing engineering
change documentation :-) At my previous employer, the factory would
always redo the documentation we sent them, so it is all
par for the course.

The problem is, showing the big picture (how to lay out the wire
and components) and zooming in on the individual connections. I've
looked at a few volt modding sites, and some of the pictures
are bad (blurry, or don't show detail where it is needed). Part
of the problem is, you need a good macro capability on the
camera, to get in close enough. With the gear I own, I couldn't
do any volt mod pictures.

Keep up the good work :-)

Paul

thank you P2B and Paul for the answers. really appreciated, will go foe
3pin then.

cheers,
geos