8.6. Other target requirements

It is important that you keep the trace length differences as small as possible to minimize skew between signals. Crosstalk on the trace port must be kept to a minimum as it can cause erroneous trace results. Stubs on these traces can cause unpredictable responses, especially at high frequencies, so ARM recommends that no stubs exist on the trace lines. If stubs are necessary, you must make them as small as possible.

The trace port clock line (TRACECLK) must be series terminated as close as possible to the pins of the driving ASIC.

The maximum capacitance that is presented by the trace connector, cabling, and interfacing logic must be less than 15pF.

For processor frequencies greater than 100MHz you must take great care in the design of the input/output pads, chip package, PCB layout, and connections to the chosen TPA. You are recommended to use SPICE modeling.

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