IEEE1394 Connections to K8V SE Deluxe m/b

[admiral_victory]

I have just installed an Asus K8V SE Deluxe m/b into a Thermaltake
"Tsunami Dream" computer case which has a cable attached to an
external Firewire socket on the case top which is meant then to be
connected to the m/b thus enabling convenient IEEE1394 compatible
peripherals easy access to the PC.

The M/B end of this cable , instead of terminating in a multi-pin
female plug to match the IEEE 1394 male connector on the m/b has 7
individual differently coloured wires which all end in single plugs
named as follows :-

Black "VG"(this also has a black extension also called "VG)
White "VP"(this has a white extension also called "VP" )
Black "GROUND"
Blue "TPA"
Orange "TPA*
Green "TPB"
Red "TPB*"

According to the Asus Manual the nine m/b header pins on the IEEE1394
mail plug are listed as follows:-

LHS RHS


"TPAO+" "TPAO-"
"GND" "GND"
"TPBO+" "TPBO-"
"+12V" "+12V"
"GND"

Can someone detail which of the coloured wires go to which terminal on
the m/b , please?

B.N.

 

[Paul]

I have just installed an Asus K8V SE Deluxe m/b into a Thermaltake
"Tsunami Dream" computer case which has a cable attached to an
external Firewire socket on the case top which is meant then to be
connected to the m/b thus enabling convenient IEEE1394 compatible
peripherals easy access to the PC.

The M/B end of this cable , instead of terminating in a multi-pin
female plug to match the IEEE 1394 male connector on the m/b has 7
individual differently coloured wires which all end in single plugs
named as follows :-

Black "VG"(this also has a black extension also called "VG)
White "VP"(this has a white extension also called "VP" )
Black "GROUND"
Blue "TPA"
Orange "TPA*
Green "TPB"
Red "TPB*"

According to the Asus Manual the nine m/b header pins on the IEEE1394
mail plug are listed as follows:-

LHS RHS


"TPAO+" "TPAO-"
"GND" "GND"
"TPBO+" "TPBO-"
"+12V" "+12V"
"GND"

Can someone detail which of the coloured wires go to which terminal on
the m/b , please?

B.N.

LHS RHS

TPA -- TPAO+ X X TPAO- -- TPA*
VG --- GND X X GND --- VG
TPB -- TPBO+ X X TPBO- -- TPB*
VP --- +12V X X +12V --- VP
X GND

On a real piece of IEEE1394 equipment, the VG and
GND should not be common. But on an Asus computer, I
think you'll find VG and GND joined together. The same
tends to be true of computer cases - they tend to
join the GND and VG together.

The typical purpose of the two GND terminals near the top
of the above picture, is as crosstalk protection signals.
Since all the GNDs are connected together, the distinction
in this case is academic.

To see how a "real" IEEE1394 host is supposed to be designed,
see figure 5 on page 13 of:

http://focus.ti.com/lit/an/slla011/slla011.pdf

Notice how Cable Ground (which Asus calls VG) is supposed to
be isolated from GND. I.e. PHY ground and LLC ground, as shown
in the figure, have a very weak DC path between them. The
1 megohm resistor is there to handle static discharge, and if
it wasn't for the need to bleed static off the 1394 cable,
even the 1 megohm resistor would be removed.

I've never heard of a computer doing 1394 properly.

Before using your computer case 1394 wiring, be aware that
case manufacturers are bad at labelling the wires correctly.
I've found on an Antec case, that TPA+ and TPA- were swapped,
as were TPB+ and TPB-. A signal you don't want to get confused,
is the VP signal (+12V). If that makes contact with the wrong
pin on an expensive 1394 equipped camera, kablammo, you are
looking at an expensive repair.

If you have an ohmmeter, verify the case wires do the following.
See page 37 of this document, for a nice picture of the pinout
of the 1394 connector:

http://developer.apple.com/document...ntosh_CPUs-G4/PowerMacG4Sept02/PowerMacG4.pdf

When using the Firewire port on the computer, I recommend that
all AC powered Firewire devices, be plugged into the same
AC power bar. That helps ensure the grounds are all at the same
potential, seeing as the computer doesn't handle grounding
properly.

Also, the safest way to connect Firewire devices, is via the
four pin version of the Firewire connector. That connector
has no VP or VG pins, so power can never be connected to a
data pin by accident. Using the four pin connector should
make Firewire as safe as USB is.

HTH,
Paul