Protocol analysis
R&S
®
RTO6
842User Manual 1801.6687.02 ─ 05
To achieve the data throughput of USB 3.1, all involved components (host, cable,
device and optional hub) must comply with USB 3.1 specifications. If any component
only complies, for example, with USB 2.0 Hi-Speed specifications, the setup works, but
limited to Hi-Speed USB data rates.
USB 3.1 also specifies a new connector format, called T
ype-C, with a reversible plug.
This small and durable connector is, however
, not mechanically compatible with
USB 2.0 connectors.
USB 3.1 Type-C connector
Figure 13-46: USB 3.1 Type-C receptacle and reversible plug
A1 to A12 = Twelve USB Type-C pins
B1 to B12 = The same USB Type-C pins as A1 to A 12, but in reverse order
* = Images courtesy of Heise Medien, Acon, phoneArena and Wikipedia author Chindi.ap
Specific protocol features
Key features of USB 3.1 Gen 1 that are addressed by option R&S R
T
O6-K570 include:
●
Since 5 Gbps is too fast for serial pattern triggering, the option uses a search-
based software trigger
●
The protocol uses a non-return-to-zero (NRZ) unclocked signal with 8b/10b encod-
ing (while USB 3.1 Gen 2 uses 128b/132b encoding)
●
The signal is scrambled with a 32-bit minimum correlation sequence
●
COMMA (K28.5), which occurs only during the reset phase, is the only unique bit
sequence
– COMMA is used for reset of the scrambling sequence, which has 32-bit mini-
mum correlation
– COMMA and packet framing are used for bit alignment
●
The protocol uses a set of different frame types that are all covered by individual
trigger and search dialogues of option R&S RTO6-K570
Frame types
All frame types are listed below. The frame types are sorted in an almost alphabetical
order, as in the oscilloscope's graphical user interface (GUI).
USB 3.1 (option R&S R
T
O6-K570)
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