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Electronics => Projects, Designs, and Technical Stuff => Topic started by: santoshgurral on May 26, 2020, 10:07:28 am

Title: PCIE edge connector Hot plug implimentation
Post by: santoshgurral on May 26, 2020, 10:07:28 am

Hi,

I want to implement hot-plug feature on my based board for PCIe raiser cards. I am referring to "PCI EXPRESS CARD ELECTROMECHANICAL SPECIFICATION, REV. 3.0" document for this feature implementation attached is the screenshot form this document.
I am designing a motherboard which has x16 PCI-E slot connector on my board. I am confused so which all PRSNT2(B17,B31,B48,B81) signals should be shorted together and connect to a pull-up. I am going to insert an x16 riser card on to my motherboard x16 slot but the x16 riser card has only x8 lanes. only the physical size of the riser card is x16.
As per the screenshot attached it says short all the PRSNT2(B17,B31,B48,B81)signals together and pullup to VCC. But if I shot all the PRSNT2 pins how come CPU will be able to differentiate between an x4/x9/x16 riser card.
Please clarify.
Thanks
Santosh

Title: Re: PCIE edge connector Hot plug implimentation
Post by: T3sl4co1l on May 26, 2020, 10:31:57 am

The interface detects active lanes, doesn't it?

Tim

Title: Re: PCIE edge connector Hot plug implimentation
Post by: santoshgurral on May 26, 2020, 01:44:47 pm

How does it identify the active lanes?