Faster debug with fewer pins: Introducing DSTREAM-HT serial trace (HSSTP) debug probe

Earlier this year, Arm introduced the DSTREAM-PT, a second generation debug probe offering support for up to 32-bit wide trace ports, giving users the bandwidth necessary for analyzing the most complex Arm based systems. You can read more about this solution in a previous article. The principal system cost of implementing this type of trace port is the pin count necessary (up to 34-pins), which in many scenarios is counter to the goals of the device.

To address this, an alternative solution, providing the trace data through a very high speed serial interface, is becoming more popular. Used in conjunction with the Arm Debugger, the new DSTREAM-HT unit is designed to support these interfaces, with the bandwidth (up to 60Gbps currently) to scale well into the future.

Serial trace solutions

Arm has produced a High Speed Serial Trace Port (HSSTP) specification, which is implemented on a number of devices. Furthermore Marvell Semiconductor have developed a similar specification known as Serial ETM (SETM). DSTREAM-HT contains decoders to support either of these protocol standards, and example debug configurations are provided for both protocols with the latest Development Studio releases, supporting reference example systems from Renesas, Xilinx, and Marvell. These configurations include the necessary target specific code to initialize and enable the HSSTP interface, and perform the necessary training steps to synchronize the probe with the target.

All of the trace functionality of the debugger is available for you, separating each source's trace stream, and synchronizing them via a global timestamp (when available). The probe has storage for 8GB of trace data, ensuring a very long history of execution can be gathered.

Flexible design for maximum compatibility

If you are working with a device not listed, don't worry. The tool includes necessary functionality to detect the features of your device. By their nature, such HSSTP ports require some initialization. This may be performed directly by some low level firmware on the target before the debugger wishes to connect, else you can allow the debugger tool to set up. The easy to use python based DTSL API allows you to implement the initialization steps directly into the configuration files. If you have a need to create such a config, we invite you to raise a support case with our team to ensure you have the best available help.

The below table shows the list of currently supported configurations - with up to 6 lanes of trace data for HSSTP (SETM is limited to 1-2 lanes), at up to 12.5 Gb/s per lane. If your configuration is not listed below, please contact Arm.

Availability

DSTREAM-HT will be available from July 2019, alongside an update to Development Studio to support the probe. A free 30-day fully featured evaluation license of Development Studio is available. The probe will be supported by all Development Studio editions.

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