Hi Renesas,
As JEDEC shown, the SPD Hub supports both open-drain mode and push-pull mode for I2C and I3C compatibility. Open-drain mode requires a pull-up resistor on board or on die, while push-pull mode doesn't. Is there already a specific function in the SPD5118 that could control the pull-up resistor on or off? If not, for board design, how could we switch-off external(on board) or internal(on-die) pull-up resistor when host-side convert to I3C (push-pull) mode from I2C(open-drain) mode?
Hi There,Thank you for posting your question online and apologies for the delay.Let us check on this and we will get back to you as soon as possible.Best Regards,OV_Renesas
Hi There,Apologies for the delay.
For the host side the pull-up resistor is supposed to be designed outside of the chip to support I2C open Drain mode.
When power up. SPD5118 is working in I2C mode, pull-up resistors are needed.
In I3C mode, there is also open drain phase, which also requires pull-up resistors, in push-pull phase the existing pull-up resistors will not interfere with the transaction of I3C if it is in the right range of value.Best Regards,OV_Renesas