IC-USB was intended for situations where the host and device are very close together, and using long wires may cause signal integrity issues. It is also recommended to use a twisted pair between the Beagle analyzer and the target system, and to keep these wires as short as possible. To minimize reflections due to impedance mismatches, a 20-40 Ohm series resistor should be added to D+ and D- between the target system and the Beagle analyzer. Please exercise extreme caution if this is required, and note that Total Phase cannot be held responsible if equipment is damaged from such activities. If the signals are not easily accessible, the wires may need to be soldered directly to IC pins or copper on the PCB. If the signal lines are easily accessible through a header or test pads, then connecting to it is straightforward. A USB cable will likely need to be cut up so the wires can be attached to the target system. The method of connecting the Beagle analyzer to the embedded bus will vary depending on how accessible the signals are on the target system. The VBUS, GND, D+, and D- lines can be connected to either the Type A or Type B connector on the Beagle analyzer using "T" connections.įigure 1: Connecting a Beagle USB analyzer to and embedded USB ![]() The D+/D- signal path of a USB does not have to be broken to be monitored by a Beagle USB protocol analyzer. This article explains how a Beagle USB protocol analyzer can be used to monitor embedded USB traffic. Some embedded systems feature embedded USBs, and it is common for these systems to have no standard USB connectors.
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