Yes, that's what I would use as resistor value.. I would use all 4 pins
in parallel, and configure them such that they can only pull High ( the
mirror image of opencollector ) which means:
 output a permanent High level 
and keep the outputs permanently active (Tristate control input = Low).
Viel Erfolg!
Peter Alfke
=======================
lenz wrote:
> 
> Hi Peter,
> 
> thank you for your response.
> 
> The datasheet of the chip which is on the add-on board states a DC
> Input Current of +/- 20mA. I have a total of 4 pins to provide power
> to the add-on board.
> The Virtex datsheet states a output current for one pin of +/- 24mA
> for LVTTL. As a novice I would expect that one pin with +/- 24mA would
> be sufficient to source the add-on board which requires +/- 20mA. Is
> this correct ?
> 
> How can I determine the value of the experiment resistor. I assume
> Vcc/Icc. Is this correct ?
> 
> Regards,
> Mark Lenz
> 
> Peter Alfke <peter@xilinx.com> wrote in message news:<3F37E2D9.290AF568@xilinx.com>...
> > Mark, your question cannot be answered without knowing the Icc
> > consumption of that extra board.
> > If it is <10 mA and not too picky about low Vcc, this might work if you
> > select the strongest Output drive for the pin ( or do you intend to use
> > multiple pins?)
> >
> > Once you know the current, you can experiment with a simple resistive
> > load. :-)
> >
> > Peter Alfke, Xilinx
> > ==========================
> > lenz wrote:
> > >
> > > Hi !
> > >
> > > I have a PCI Mezzanine Card (PMC) with a Virtex 400 and a front panel
> > > connector. The Virtex is connected to the SCSI-2 style front panel
> > > connector with 68 pins.These pins are interleaved signal and ground
> > > pairs.So, I have 34 free I/O at the front panel connector.
> > >
> > > I would like to connect a little add-on board to this front panel
> > > connector. This board will be populated with a Gigabit Ethernet
> > > Controller (PMC-Sierra PM3387). Besides data and control signals I
> > > have to provide power to the add-on board.
> > >
> > > I am planning to connect the add-on board VCC plane with the I/O pins
> > > at the front panel connector. Then the Virtex will drive '1' at the
> > > front panel connector I/O. The add-on board ground plane will be
> > > connected with the ground pins at the front panel connector.
> > >
> > > Can this provide sufficient power to the add-on board ?
> > > Is there a better way to provide power ?
> > >
> > > Thanks in advance.
> > >
> > > Mark Lenz

Hi Peter,

thank you for your response.

The datasheet of the chip which is on the add-on board states a DC
Input Current of +/- 20mA. I have a total of 4 pins to provide power
to the add-on board.
The Virtex datsheet states a output current for one pin of +/- 24mA
for LVTTL. As a novice I would expect that one pin with +/- 24mA would
be sufficient to source the add-on board which requires +/- 20mA. Is
this correct ?

How can I determine the value of the experiment resistor. I assume
Vcc/Icc. Is this correct ?

Regards,
Mark Lenz


Peter Alfke <peter@xilinx.com> wrote in message news:<3F37E2D9.290AF568@xilinx.com>...
> Mark, your question cannot be answered without knowing the Icc
> consumption of that extra board.
> If it is <10 mA and not too picky about low Vcc, this might work if you
> select the strongest Output drive for the pin ( or do you intend to use
> multiple pins?)
> 
> Once you know the current, you can experiment with a simple resistive
> load. :-)
> 
> Peter Alfke, Xilinx
> ==========================
> lenz wrote:
> > 
> > Hi !
> > 
> > I have a PCI Mezzanine Card (PMC) with a Virtex 400 and a front panel
> > connector. The Virtex is connected to the SCSI-2 style front panel
> > connector with 68 pins.These pins are interleaved signal and ground
> > pairs.So, I have 34 free I/O at the front panel connector.
> > 
> > I would like to connect a little add-on board to this front panel
> > connector. This board will be populated with a Gigabit Ethernet
> > Controller (PMC-Sierra PM3387). Besides data and control signals I
> > have to provide power to the add-on board.
> > 
> > I am planning to connect the add-on board VCC plane with the I/O pins
> > at the front panel connector. Then the Virtex will drive '1' at the
> > front panel connector I/O. The add-on board ground plane will be
> > connected with the ground pins at the front panel connector.
> > 
> > Can this provide sufficient power to the add-on board ?
> > Is there a better way to provide power ?
> > 
> > Thanks in advance.
> > 
> > Mark Lenz

Mark, your question cannot be answered without knowing the Icc
consumption of that extra board.
If it is <10 mA and not too picky about low Vcc, this might work if you
select the strongest Output drive for the pin ( or do you intend to use
multiple pins?)

Once you know the current, you can experiment with a simple resistive
load. :-)

Peter Alfke, Xilinx
==========================
lenz wrote:
> 
> Hi !
> 
> I have a PCI Mezzanine Card (PMC) with a Virtex 400 and a front panel
> connector. The Virtex is connected to the SCSI-2 style front panel
> connector with 68 pins.These pins are interleaved signal and ground
> pairs.So, I have 34 free I/O at the front panel connector.
> 
> I would like to connect a little add-on board to this front panel
> connector. This board will be populated with a Gigabit Ethernet
> Controller (PMC-Sierra PM3387). Besides data and control signals I
> have to provide power to the add-on board.
> 
> I am planning to connect the add-on board VCC plane with the I/O pins
> at the front panel connector. Then the Virtex will drive '1' at the
> front panel connector I/O. The add-on board ground plane will be
> connected with the ground pins at the front panel connector.
> 
> Can this provide sufficient power to the add-on board ?
> Is there a better way to provide power ?
> 
> Thanks in advance.
> 
> Mark Lenz

Hi !

I have a PCI Mezzanine Card (PMC) with a Virtex 400 and a front panel
connector. The Virtex is connected to the SCSI-2 style front panel
connector with 68 pins.These pins are interleaved signal and ground
pairs.So, I have 34 free I/O at the front panel connector.
  
I would like to connect a little add-on board to this front panel
connector. This board will be populated with a Gigabit Ethernet
Controller (PMC-Sierra PM3387). Besides data and control signals I
have to provide power to the add-on board.

I am planning to connect the add-on board VCC plane with the I/O pins
at the front panel connector. Then the Virtex will drive '1' at the
front panel connector I/O. The add-on board ground plane will be
connected with the ground pins at the front panel connector.

Can this provide sufficient power to the add-on board ?
Is there a better way to provide power ?

Thanks in advance.

Mark Lenz