Reading measurements from the UCD9240 using PMBus commands

Mohamed,

TI provides the Fusion Digital Power Designer software package, which includes several tools that are capable of communicating with the UCD92xx series of controllers from a Windows based host computer.  It requires the use of a USB Interface Adapter EVM (http://focus.ti.com/docs/toolsw/folders/print/usb-to-gpio.html) to connect between the SMBus (I2C) interface of the UCD92xx controller and the USB port on the computer.  The software is designed to interface to the controller only through this device.  There should have been a coupon or some other documentation along with the ML605 evaluation board which allows you to purchase this EVM at a discount.

If you have another means of communicating over the SMBus(I2C) interface and it can be programmed to write the properly formatted commands then this will work.  You can reference the UCD92xx PMBus Command Reference (http://focus.ti.com/general/docs/lit/getliterature.tsp?literatureNumber=sluu337&fileType=pdf) and the PMBus Specifications at http://pmbus.org/specs.html for the command codes and data formating. 

Hi Brad,

Thanks a lot for your reply.

I already have the USB EVM adapter and I have used it together with the Fusion Digital Power program. I was able to monitor all the needed parameters through the software. However, in my case, this monitoring has to be done "on-chip" (i.e. within the FPGA). Last week, I was able to find a "freeware" implementation of PMBus from TI. The implementation is for a TI MSP430 USCI chip interfaced to a UCD91xx chip (http://focus.ti.com/general/docs/litabsmultiplefilelist.tsp?literatureNumber=slaa386a). I modified the implementation to adapt it to Microblaze and UCD9240. Now, I have it working fine on the FPGA.

Mohamed