Teledyne LeCroy Detective - Users Manual - Manual (Page 7)

CATC CATC Detective User’s Manual Version 2.21
Page 4
2.4 The Detective USB Probe
The Detective USB probe is an external box, about 4.5
Ч
2.5
Ч
1.5 inches, with a female DB15
connector on one side and two USB connectors (one A-type and one B-type) on the other. The
probe is designed to connect to any point in the USB system as a passive listening device,
without interfering with bus traffic. See the System Setup section for details on connecting the
Probe to a system.
In addition to physically connecting the analyzer to the USB system, the Probe includes special
circuitry to assist in generating an external trigger signal. Two components are associated with
this external trigger mechanism:
•
The 10 pin trigger header
•
The TRIG push button
Inside the CATC Detective Probe box is a 10-pin external triggering header, arranged in 5 rows
of 2 pins each, and easily accessed through an opening in the protective cover of the Probe. The
triggering header signal pin assignment is detailed below:
GND
TRIG
GND
TRIG
TRIG is an external trigger input to the CATC Detective system, and is duplicated on 2 of the
pins as marked. This signal is tied through a 4.7k
Ω
pull-up resistor to Vcc on the Detective ISA
card, and is connected to the input of a FAST logic circuit. To activate the external trigger signal,
it must be pulled to a TTL-low level for at least 8 USB bit times (0.67 microseconds for a full
speed branch and 5.33 microseconds for a low speed branch). When the Detective software is set
to record using an external trigger mode (External Start or External Stop), the low level on this
pin will activate either the start or the end of the recording session.
The TRIG push button is located on top of the Detective Probe box, and can be used to manually
generate the external trigger signal. To activate this feature, the analyzer must be in either the
PC
USB USB
TRIG
Detective Probe
DB15 connector
Type “A” Type “B”
USB connectors