Teledyne LeCroy QPHY-USB - Manual (Page 43)

QPHY-USB Software Option
QPHY-USB Operator’s Manual Rev F
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5. From the HS Electrical Test Tool - Device Command menu, select TEST_SE0_NAK from the Device
Command drop down menu. Click EXECUTE once to place the device into TEST_SE0_NAK test mode.
Figure 46. Use Device Command drop down list of HS Electrical Test Tool
6. Place the TEST/INIT on the Test Fixture to the TEST position. This switches in the data generator in place
of the host controller. The data generator emulates the “IN” packets from the host controller.
7. Verify that there is a response packet (NAK) for all packets sent from the data generator. This should
appear as a sequence of two packets with a small gap between them followed by a larger gap as shown
in the figure below. The first packet is the data generator output and the second packet is the NAK from
the device or hub under test. If there is a response for every packet sent by the generator than the device
or hub passes EL_18.
Figure 47. Response to IN tokens with 12-bit sync - all packets NAK’d