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.

End of packet trigger

D+,–

Bus Idle

D–,+

SOP

SE0 portion of EOP

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Agilent Technologies 41A, 54621D, 24A, 42A, 54621A, 22A manual To use USB triggering