From: lenz19@gmx.de (lenz) Newsgroups: comp.arch.fpga Subject: Virtex "Virtual VCC" Date: 11 Aug 2003 11:13:45 -0700 Organization: http://groups.google.com/ Lines: 23 Message-ID: <7f673150.0308111013.32327322@posting.google.com> NNTP-Posting-Host: 193.175.135.35 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit X-Trace: posting.google.com 1060625626 16105 127.0.0.1 (11 Aug 2003 18:13:46 GMT) X-Complaints-To: groups-abuse@google.com NNTP-Posting-Date: 11 Aug 2003 18:13:46 GMT Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!switch.ch!news.mailgate.org!cyclone.bc.net!newsfeed.stanford.edu!postnews1.google.com!not-for-mail Xref: chonsp.franklin.ch comp.arch.fpga:31757 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 ###### From: lenz19@gmx.de (lenz) Newsgroups: comp.arch.fpga Subject: Re: Virtex "Virtual VCC" Date: 12 Aug 2003 05:16:34 -0700 Organization: http://groups.google.com/ Lines: 56 Message-ID: <7f673150.0308120416.31cdfa9e@posting.google.com> References: <7f673150.0308111013.32327322@posting.google.com> <3F37E2D9.290AF568@xilinx.com> NNTP-Posting-Host: 195.37.78.89 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit X-Trace: posting.google.com 1060690596 27202 127.0.0.1 (12 Aug 2003 12:16:36 GMT) X-Complaints-To: groups-abuse@google.com NNTP-Posting-Date: 12 Aug 2003 12:16:36 GMT Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!switch.ch!news.mailgate.org!cyclone.bc.net!newsfeed.stanford.edu!postnews1.google.com!not-for-mail Xref: chonsp.franklin.ch comp.arch.fpga:31790 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 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 ###### From: Peter Alfke Newsgroups: comp.arch.fpga Subject: Re: Virtex "Virtual VCC" Date: Tue, 12 Aug 2003 08:55:21 -0700 Organization: Xilinx,Inc Lines: 65 Message-ID: <3F390DE8.8D6FD685@xilinx.com> References: <7f673150.0308111013.32327322@posting.google.com> <3F37E2D9.290AF568@xilinx.com> <7f673150.0308120416.31cdfa9e@posting.google.com> NNTP-Posting-Host: peter.xilinx.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Mailer: Mozilla 4.77C-CCK-MCD {C-UDP; EBM-APPLE} (Macintosh; U; PPC) X-Accept-Language: en To: lenz Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!switch.ch!news.mailgate.org!nntp.infostrada.it!in.100proofnews.com!in.100proofnews.com!attla2!attla1!ip.att.net!newsgate.xilinx.com!cliff.xsj.xilinx.com!not-for-mail Xref: chonsp.franklin.ch comp.arch.fpga:31767 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 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