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Triggering the Oscilloscope
To use USB triggering
3Press the D+ and D– softkeys to select the channel connected to the USB
signal D+ and D– lines. The
D+ and D– labels for the source channels
are automatically set.
As you press the D+ or D– softkey (or rotate the Entry knob on mixed-signal
oscilloscopes), the
D+ and D– label for the source channel is automatically set
and the channel you select is shown in the upper-right corner of the display
next to "USB".
Adjust the trigger level for the selected analog channel by turning the Trigger
Level knob. Select Threshold in the D7 Thru D0 or D15 Thru D8 menu to set the
level for digital channels. The value of the trigger level or digital threshold is
displayed in the upper-right corner of the display.
4Press the Trigger: softkey to select where the USB trigger will occur:
SOP (Start of Packet) - triggers at the Sync bit at the beginning of the packet.
EOP (End of Packet) - triggers at the end of the SE0 portion of the EOP.
RC (Reset Complete) - triggers when SE0 is > 10 ms.
Suspend (Enter Suspend) - triggers when the bus is idle > 3 ms.
Exit Sus (Exit Suspend) - triggers when exiting an idle state > 10 ms. This is
used to see the suspend/resume transition.
+,–
D–,+
Bus Idle
SOP
SE0 portion of EOP
End of packet trigger
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