1 Reply Latest reply on Jun 29, 2020 6:39 PM by bhfletcher

    Ultra96 Anyone tried to use the HS Connector with 1.8V logic

    100charlesb

      I am aware that the HS connector uses 1.2V logic but is there a way to bodge it to operate with 1.8V logic?

      I notice the VCCO_HP rail is powered by a TPS6508641 (LDO03A) which can be programmed to 1.5 volt

      then looking at Xilinx DS925 it seems that at VCCO + 0.3V the HP bank can operate at 100% of UI (unit interval).

      I suspect it would not be possible to cut the track and insert 1.8V as it is a multi-layer board.

       

      I made a little adapter board that connects the Ultra96 to a high speed ADC but had assumed it was all 1.8v

      logic so I am scuppered if I can't find a work around.

       

       

      - Charles

        • Re: Ultra96 Anyone tried to use the HS Connector with 1.8V logic
          bhfletcher

          For both Ultra96-V1 and Ultra96-V2, the HS Connector has a total of 34 PL IOs as follows:

          • 2 from Bank 26 with VCCO = 1.8V -- I assume this is not enough for what you need
          • 32 from Bank 65/66 with VCCO = 1.2V

           

          I think what you propose may work with the Ultra96-V1. Please let us know if reprogramming the TPS6508641 to 1.5V worked.

           

          For those who have the same question with Ultra96-V2, I will add a bit more analysis. The Ultra96-V2 has a bit more flexibility given the Infineon PMICs allow more programmable voltage range, but a design decision to combine the 1.2V HP Bank rail and the 1.2V USB Hub rail complicates things.

           

          Looking at the Bank 65/66 VCCO specifically for Ultra96-V2:

          • VCCO_65 is tied to net +VCCO_HP
          • VCCO_66 is tied internally to VCCO_65, so also +VCCO_HP
          • +VCCO_HP is Channel B output of U11, PMIC IRPS5401, Addres = 0x13
          • +VCCO_HP is programmed to operate at 1.2V and 2.0A
          • Besides VCCO_65, what else is connected to +VCCO_HP?
            • Pull-up for FAN_PWM control, which is also on Bank 65
            • VDD12 on U16, Microchip USB5744 USB Controller Hub
              • VDD12 Abs Max = 1.32V

           

          Since the PMIC is a programmable device, you could use the Infineon tools and Dongle to reprogram 0x13 Channel B output voltage to 1.8V. However, that exceeds the USB5744 absolute max on VDD12. If you didn't care about the USB functionality on Ultra96-V2 and you had the means, you could remove the USB5744 and then reprogram U11 to do what you want.

           

          It might be easier to switch to something that is a lot more versatile like the UltraZed-EG platform.

           

          Bryan

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