USB4/TBT3 Sideband (SB) Channel

USB4 can simultaneously transmit DisplayPort video and PCIE signals through Intel Tunneled technology, and also support PD (Power Delivery) fast charging technology.
USB4 is backward compatible with USB 2.0 and USB 3.2 Gen1/Gen2 and supports Thunderbolt 3/4. The sideband channel (SB) was originally defined as a channel for video protocol communication after entering the Alt-Mode (Alternate Mode) in USB 3.2 (for example: DP Alt-Mode transmits AUX signals through the Sideband channel...etc.). In the USB4 specification, new features of Sideband channel are added to confirm whether the USB4 interface is connected, start and close the channel, initialize the channel, and enter or leave the sleep mode. Thunderbolt Alt-Mode will be enabled when connecting to the device via Thunderbolt 3.

Application: The connection between the USB4/TBT3 Ports of two interconnected Routers that provides initial communication and setup functionality.
Signal: Sideband Transactions are sent over SBTX and received over the SBRX
Voltage: 3.3V

This protocol specifies that when using a Type-C connector for USB4/TBT3, can be measured directly from the SBU (Sideband Unit) pins.
It is also possible to purchase a USB Type C Fixture for measurement purposes.

Its function is to assist in the communication of high-speed signal transmission, mainly for the following purposes:
‧ Negotiate Link Parameters
‧ Lanes
‧ Gen
‧ Coding
‧ Lane Equalization Management

‧ Can enabled the Sideband TX/RX dual-channel analysis mode.
‧ The TX / RX channel can be selected for analysis in the data convert field.
‧ Choose which channel to display in the report area, and both channels can be displayed at the same time.
‧ Show scale on data convert
‧ Show data detail on report

Report Diagram:



Protocol Quick Setup:

① Quickly establish the necessary channels and related settings for the logic analyzer capture.         


② Choose the Desired Protocol Decode     

③ The quick setup will automatically configure the sampling rate and trigger level according to default conditions.  

④ Click on the icon to access the protocol parameters configuration screen. 

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