TPS65994AE: TPS65994AE I2C Port functionality and mapping

I2C_EC (I2C1s) and I2C2s works the same so they can interchanger the processor and ASM4242.

Are you designing a new product? Assuming it is a PC/NB design, what reference design you are following? Are you looking to pass compliance?

Thanks Tommy Lin for the clarification.

Yes, this is a new product.

It is an embedded product, so we only need it to work. Compliance is not required for this application. 

I'll get back to you on the reference design.

For new designs I would not recommend using TPS65994AE as this is an older device that we can offer limited FW support.

ASM4242 should've updated their AVL and included our newer gen device but that will require NDA to get access on device information

Our current hardware is based on the ASMedia AT1070 reference design. We are currently finishing a new revision, so we are investigating upgrading to the latest. I'm working with Ben Moyers (18487829), who has an NDA in place with TI. I'm also working on getting one in place for my consulting company.

It turns out we have an NDA with ASMedia, and as late as 2026-03-31, they were still pointing us at the AT1070 reference design, so still trying to sort this out ...

Got it. Our recommendation here would be using the newer NDA device as TPS65944AE is a device that is 4 years old with basically no patch space left. If you need to setup an NDA with TI I can direct you to our field team to get the process going

Thanks for the direction. I started the NDA process with support@ti.com. However, not sure how quickly they will process it, so any pointers you have to sales support in OH, USA, would be appreciated. 

A little more background on what we are doing: we are adding USB4 to an Nvidia AGX Orin-based design. We understand this is a big project as the host is ARM instead of x86, but with high-end edge AI systems proliferating (the market we serve) this need is increasing. Additionally, Qualcomm and likely others are coming out with USB4 in their high-end ARM chips.

This is interesting.  Is there a direct replacement for the TPS65994AE?

Hi Tommy,

As Cliff has said, he is working with me on this project and I already have an NDA with TI from Openity.  Feel free to private message me if there are items you can only disclose or share under NDA.

Jeff is also on the team and covered by bi-directional NDAs with Openity as well.

Cliff and Jeff,

Reaching out to the regional sale manager here will likely be faster.

Here's the contact info of the RSMs

Nic Gough (n-gough@ti.com)

Shawn Randell (randell@ti.com)

Ben,

I will send you a private message later

Tommy Lin How tightly coupled is the ASM4242 firmware to the TI PD firmware? If we switch out the TPS65994AE for a newer part, will the ASM4242 firmware need to change as well?

That part I am not entirely sure as this depends on how you are going to implement the PDFW update. The newer part has a slightly different FW update process compare to TPS65994AE. However the register read write interaction between PD and ASM4242 remains the same.

Thanks, that is good news - hopefully our efforts working on the current hardware will be useful wherever we end up!

The PDFW is a good question, as we have been programming the TPS EEPROM with an external programmer. In this application, we can somewhat control what is going to be plugged into it. Looking at the list of TPS firmware updates, it appears many are to fix compatibility/certification issues. In a somewhat controlled industrial environment, is PDFW required? Should we be thinking differently about this?

Our needs are fairly modest: we are only doing DFP-only / 5V, 3A. Ports will always be host - no DR/PR Swap. Functionally, we need USB4 20/40G, and PCIe/USB3/DP tunneling over USB4. Does this scope impact the feasibility of using the TPS65994AE vs a newer part?

I would recommend using the newer device (sent a message to Ben about the device name hopefully you got the device name by now) here for future proofing as the newer device is flash based while TPS65994AE is ROM based. The newer device does not have EEPROM so you just program the FW directly to the PD

TPS65994AE also cannot pass the latest USBIF compliance standards so if compliance is a concern you should consider using the newer device.

Based on your requirement we have a variant in our new device that fits your need.