Help in selecting right PCI/PCI express slots

Discussion in 'General Electronics Chat' started by ak52, Mar 25, 2015.

  1. ak52

    Thread Starter Member

    Oct 15, 2014
    145
    4
    Hey guys,
    I am working on a new project where in i plan to have a daughter card and a base card.
    The daughter card is more like the CPU from which has about 300 pin terminals which i need to bring down to the base card.
    I would like to use the PCI express slots as they have a high pin count in a small space.
    I do not know the correct terminology dealing with these connectors,
    but do PCI express slots come in male / female types?
    My plan is to solder the female connectors on the daughter card and the male in the base card.

    Thanks in advance,
    AK
     
  2. AnalogKid

    Distinguished Member

    Aug 1, 2013
    4,515
    1,246
    PCI and PCIe come from the personal computer market, and as such still use 1-piece connectors. The daughter card has gold plated tabs along the edge of the pc board, and the motherboard has an edge connector. PCIe has three different connector sizes depending on the number of high-speed "lanes" being connected. Photos of a typical daughter card edge finger area and the motherboard connectors are here:
    http://en.wikipedia.org/wiki/PCI_Express

    PCIe is a relativly dense connector system for edge fingers, but is nothing compared to the Multi-gig connectors used in VPX or something like Samtec's SEARAY series. What kind of signals are you moving, and how much room do you have? Any high-speed serial stuff? Power? Photos? Schematic? ...?

    ak
     
  3. Brownout

    Well-Known Member

    Jan 10, 2012
    2,375
    998
    The answer is 'no'. PCI and PCIe are standard connectors, and are available only as sockets. BTW, PCI is an old technology and is considered obsolete. As such, it's becoming more rare in newer motherboards, although still used heavily in industrial backplane systems. Either way, you'll need custom software drivers to use your plug in board, and that can be a show-stopper. Drivers are difficult to write, to say the least, and some OS's are making it ever harder.
     
  4. ak52

    Thread Starter Member

    Oct 15, 2014
    145
    4
    The signals are all mixed,meaning they include power lines ,communication lines-ethernet,usb,rs232,spi ,rs485 and a few others,and a lot of digital and analog signals.
    I chose PCI express solely because of the high pin count,i am not interested in how it actually communicates.,but as Mr Brownout pointed there is no male/female connector in PCI express shots,that leaves me with two options:
    1.Convert my daughter PCB as an edge connector,(like a DIM stick) and use the PCI express socket.
    2.Use customized connectors with a pitch size of <1.27mm like :
    Samtec-SFML-040-01-L-D.png Samtec-TFML-040-01-L-D.png

    The second option seems less complicated to me,any other ideas please let me know.

    Thanks in advance
    AK
     
  5. Brownout

    Well-Known Member

    Jan 10, 2012
    2,375
    998
    I don't understand what you're saying. PCI/PCIe are strict standards concerning the connection dimensions. Only connectors that are constructed to the specification will work. Your daughter board needs to have a standard PCI or PCIe connector if you are going to plug it into a motherboard.
     
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