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#1 2009-07-20 8:34 pm
- teeck2000
- Member
- Registered: 2009-07-20
- Posts: 2
How can I find the pinout of a connector on the motherboard?
Hello,
I am looking for some help on figuring out the pinout to a non standard pcie x1 lane connector. I have a new mac mini that has a 30 pin connection on the motherboard, which connects the wifi/bluetooth that I have confirmed with apple is a PCIe x1. I have been able to find the 3.3v pins and the negative and positive 66 mhz Clock pins, but nothing else. I was hoping someone would know how to find the pinouts with measuring equipment. I am currently using a 100mhz oscilloscope. Does anyone have any experience with something like this? I was hoping to measure the signals on another motherboard with a standard PCIe and then by comparing with measurements on the mac mini connecter, find which pin is which, but, alas that has not worked.
Here is a picture
http://img140.imageshack.us/i/macmini5.jpg/
Thanks!
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#2 2009-07-21 2:00 am
Re: How can I find the pinout of a connector on the motherboard?
Normal PCI-E 1x is 36 pins, so are you 100% sure that the slot is a PCI-E pinout with some missing?
The older Mac minis did have a 36+16 pin PCI-E connector, not sure what model 2,1 uses.
Anyway, to find the pins you'll want to look up how LVDS works and try to find the minute voltage differentiations on pairs of pins, hopefully that are next to each other.
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#3 2009-07-21 2:53 am
- teeck2000
- Member
- Registered: 2009-07-20
- Posts: 2
Re: How can I find the pinout of a connector on the motherboard?
Yeah I talked to apple and they said it was a PCIe x1 lane. There are a bunch of reserved pins on the PCIe pins so its missing some that are not needed. I have found the wake, clock pins, 3.3v power pins and GND pins. I have read up on the LVDS but I don't know how to measure it on the scope. The voltage keeps going up and down and I just get noise on the scope.
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#4 2009-07-21 4:04 pm
- Mr. T
- Best of both worlds
- From: omnipresent
- Registered: 2002-04-02
- Posts: 4226
Re: How can I find the pinout of a connector on the motherboard?
Wow, I haven't used a scope since a circuits class I took a few years back. I can vividly recall circuit diagrams, Karnaugh maps, and the smoke you get when you install a chip backwards.
Anyway, I would blindly speculate that the differential pairs will be inactive unless a PCIe device is detected. One thing you might try is to trace the data pins back to the controller, and try to find out what they do from the controller pinout.
Last edited by Mr. T (2009-07-21 4:05 pm)
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