Bridge

5.4.5Example USB Bus Analyzer (CATC) Traces

Figure 5-17below shows the USB data transmissions between the bridge and the host PC captured with the USB CATC Bus Analyzer. In this example, the Right Shift + ‘g’, ‘h’ keys were typed followed by the ‘Volume Up’, ‘Volume Down’ keys. Note the keyboard regular key reports are sent to the PC via the endpoint 1 while the Multimedia key reports are sent via the endpoint 2 with Report ID 2.

Figure 5-17. Example keyboard CATC Trace (Standard and MM Keys)

Keyboard EP (EP1)

Modifier Byte.

“g” Key code.

“h” Key code.

 

Right Shift Key Down

Key Down

Key Down

“h” Key Up

“g” Key Up

“Volume + ” Key Down

“Volume + ”

Key Up

Endpoint 2, Report ID 2 =

Multimedia keys

CY4672 Reference Design Guide, Document # 001-16968 Revision **

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Cypress CY4672 manual Example USB Bus Analyzer Catc Traces, Example keyboard Catc Trace Standard and MM Keys