Hello, i know this subject has came up before and I'm the next guy. I found out a server motherboard a friend of mine gave me has i2c on it. I was wondering other then seeing what i2c address is there anything I need to do to see if anything is coming from the motherboard to be able to read it through serial monitor using an arduino to see what is on it?
Sorry this is all new to me. I'm at the moment trying to figure out the pinout of his i2c port. There is no document not even in the manual about the pinout for this port.
tl;dr: without more information, you'll waste time on this.
I've not seen anything with an I2C port on it. Most legitimate use of that bus is as intended - communication over very short distances, like all on one PCB. Or just the short hop it might be to a display or other I2C based external circuitry.
So maybe just hooking up your logic analyser* to the SCL and SDA lines might show some of that internal traffic.
If that port is for anything other than diagnostic use:
First would be knowing whether the roll of the motherboard I2C was to serve as a master or a slave.
Theoretically you could assume it is a master, and set up some kind of generic address tolerant (or ignorant listener) and see what the master's traffic consisted in.
If it is a slave, you can find the address, but then you are stuck as just about anything can be sent across the bus to things hanging on it. Without knowing what it was meant to control or talk to, you'd not get too far looking at the first transmission and woukd be unable to respond to continue the dialogue.
If you had two devices, the one you have and whatever it was meant to talk to, you could use your logic analyser* to grab up the traffic and look into trying to figure out what was being accomplished over the bus.
*_you don't have a logic analyser? Ask Santa to get you one! These are inexpensive and work quite well:
Shop around for it, spend as little as you dare and decide how long you want to wait for it to get to your place.
If you are talking about a PC motherboard it is used for internal communication. Things like BIOS settings, voltage monitoring and temperature monitoring. It is not meant for external connections.
Thank you all for the reply back, I messend up. I forgot to put in tthe subject which motherboard it is. The motherboard my friend gave to me is a supermicro X12SDV-8C. I honestly didn't know anything about this board.
I looked up the manual https://www.supermicro.com/manuals/motherboard/X12/MNL-2440.pdf and saw there is an i2c on the board no reference on the manual to what type of i2c. I'm still going through the manual about 60 pages. I also found out it has 3 i2c on it. Some are bus management controls. But this one that says JPI2C1 cought my attention. I wanted to find out more about it. and see What i can read from it.
I also found out there are some GPIO pins as well on -SGPIO1.
I understand it's for IMPI. I was just wondering If It is possible to read out the information on it. I have saw some other sites and forms Saying some people tooked displays to them and was able to read out information and other say they was unable to get anything.
Which brings me back to here before attempting to do anything I would asked in here first.