4 Replies Latest reply on Apr 7, 2010 8:29 AM by Davide

    US15W: How to enable I2C mode (I2C_EN) on Intel SMBus controller.

    Green Belt

      Is it possible to enable the I2C mode on the US15W (Poulsbo) chipset from Intel?

      If it is possible, how can it be done?

        • Re: US15W: How to enable I2C mode (I2C_EN) on Intel SMBus controller.
          Felix_M BlackBelt

          Hi Dominik:


          Since you are using Intel® US15W System Controller Hub, I want to make you aware of a special place to go with your technical questions.  The Intel e-Help desk is staffed by Intel representatives dedicated to answering embedded Intel® architecture product, design and development questions for select Intel processors, including Atom and US15W.  


          The Intel e-Help desk is only available to registered private users.  Before you can access e-Help, you will first have to upgrade your community membership to private status.  Private account status also allows you to access special documents and tools at the Intel® Embedded Design Center.


          Note that it usually takes a few days for the approval process, and it normally requires that your company has a Non-Disclosure Agreement (NDA) with Intel.  If you are interested, Click here to go to your ‘My Account’ page and request registered private access. 


          In the meantime, let's see if someone in the community can help you with an answer.





          • Re: US15W: How to enable I2C mode (I2C_EN) on Intel SMBus controller.
            Green Belt
            There is no I2C_EN bit to disable SMBus behavior according to the US15W datasheet. My problem is that I can't clear bit 0 (Completion Status) of the Host Status Register (HSTS) before transaction start. The HSTS status register does not allow to be cleared and always returnes 01h. I had been trying to clear it many times, but no luck. If it is cleared, HSTS returns 00h and SPD read access will be performed successfully.

            [*]LPC Controller Location:
            Bus:00 Dev:1F Func:00

            [*]LPC Controller Vendor/Device:
            VendorID:8086 DeviceID:8119

            [*]SMBUS Base Address Register:
            I/O Base:00000400

            [*]SPD Initialization at address 50h
            Attempt: 01, Reseted HSTS:01
            Attempt: 02, Reseted HSTS:01
            Attempt: 03, Reseted HSTS:01
            Attempt: 04, Reseted HSTS:01
            Attempt: 05, Reseted HSTS:01
            Attempt: 06, Reseted HSTS:01
            Attempt: 07, Reseted HSTS:01
            Attempt: 08, Reseted HSTS:01
            Attempt: 09, Reseted HSTS:01
            Attempt: 10, Reseted HSTS:01
            Attempt: 11, Reseted HSTS:01
            Attempt: 12, Reseted HSTS:01
            Attempt: 13, Reseted HSTS:01
            Attempt: 14, Reseted HSTS:01
            Attempt: 15, Reseted HSTS:01
            Some status bits cannot be cleared. Exiting...