About Trace Signals; Figure 2-5 Clock Waveforms; Table 2-6 Traceclk Frequencies - ARM DSTREAM-ST System And Interface Design Reference Manual

2.4

About trace signals

Data transfer is synchronized by the TRACECLK signal.
Clock frequency
For capturing trace port signals synchronous to TRACECLK, the DSTREAM-ST trace feature supports
up to 600Mbps per trace signal using DDR clocking mode.
To achieve the maximum trace data rate, use the short (15cm) cable provided with DSTREAM-ST.
The following figure and table describe the timing for TRACECLK:
Parameter
Tperiod (min)
Twh (min)
Twl (min)
Switching thresholds
The trace probe detects the target signaling reference voltage (VTRef) and automatically adjusts its
switching thresholds to VTRef/2. For example, on a 3.3V target system, the switching thresholds are set
to 1.65V.
Hot-plugging
If you power-up the DSTREAM-ST unit when it is plugged into an unpowered target, or if you plug an
unpowered DSTREAM-ST unit into a powered target, trace functionality is not damaged.
If you connect an unpowered DSTREAM-ST unit to a powered target, there is a maximum leakage
current into the DSTREAM-ST unit of ±10μA on any of the debug or trace signals.
ARM 100893_0100_00_en
Note
DSTREAM-ST
2.08ns
1.0ns
1.0ns
Copyright © 2017 ARM Limited or its affiliates. All rights reserved.
2 ARM
Tperiod
Twh
Description
Clock period
High pulse width
Low pulse width
Non-Confidential
DSTREAM-ST target interface connections
®
2.4 About trace signals
Twl

Figure 2-5 Clock waveforms

Table 2-6 TRACECLK frequencies

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