One of the key goals for USB4 is to retain compatibility with the existing ecosystem of USB3.2, USB 2.0 and Thunderbolt  products, and the resulting connection scales to the best mutual capability of the devices being connected. USB4 is designed to work with older versions of USB and Thunderbolt . USB4 Fabric support high throughput interconnects of 10 Gbps (for Gen 2) and 20 Gbps (for Gen 3) and supports Thunderbolt 3-compatible rates of 10.3125 Gbps (for Gen 2) and 20.625 Gbps (for Gen 3). It becomes very important to verify the Thunderbolt  backward compatibility with the designs. Though the support of USB4 Interoperability with Thunderbolt  3 (TBT3) is optional in USB4 host or USB4 peripheral device and required USB4 Hub and USB4 Based Dock but it is very essential to work in the existing ecosystem. 

Few Main features of USB4 Interoperability with Thunderbolt  3 (TBT3) Systems

• Support for Bi-Directional Pins & Retimers: TBT3 Active Cables can contain two bidirectional Re-timers which have the capability to send AT Responses on its RX channel. Router connected directly to such Retimer needs to support A Router that is connected directly to a bidirectional Re-timer shall support reception of Transactions on both TX and RX channels. 

• Bounce Mechanism: This feature is used by Router to access the Register Space of a Cable Re-timer that can only be accessed by its Link Partner.
• Asymmetric Negotiation: The Router which connects with Cable Retimers needs to follow Asymmetric TxFFE in Phase 5 of Lane Initialization. 
• USB4 Link Transitions: In TBT3 mode, the configuration of two independent Single Lane Links can be used non-transient state or Single Lane Link just using the Lane1 Adapter.

Cadence has a mature USB4 Verification IP solution that can help in the verification of USB4 designs with TBT3. Cadence has taken an active part in the Cairo group that defined the USB4 specification and has created a comprehensive Verification IP that is being used by multiple members. If you plan to have a USB4-compatible design, you can reduce the risk of adopting new technology by using our proven and mature USB4 Verification IP. Please contact your Cadence local account team, for more details.

The coronavirus has helped make Big Tech too big to fail. Before the pandemic, political pressure in D.C. and Brussels was mounting on Silicon Valley giants like Facebook. Gina Chon explains how their size has been an asset in a crisis, which will mute arguments to break them up.

The coronavirus has helped make Big Tech too big to fail. Before the pandemic, political pressure in D.C. and Brussels was mounting on Silicon Valley giants like Facebook. Gina Chon explains how their size has been an asset in a crisis, which will mute arguments to break them up.