ARM Technical Support Knowledge Articles

How do I configure DSTREAM/RVI to connect to a target using Serial Wire Debug (SWD)?

Applies to: RealView ICE and Trace (RVI / RVT)


Serial Wire Debug (SWD) is an alternative debug method to JTAG.  Unlike JTAG, SWD uses 2-pins to pass data to and from the target system.  SWD can only be used to debug CoreSighttm systems.

The following FAQ discusses how to configure RVI to use SWD.

If you are using an RVI unit :

In order to use SWD you must use the newest version of the LVDS probe. The version of the LVDS probe can be identified by the part number on the PCB silkscreen: The new LVDS probe is marked HPI 0151. The older LVDS probe is marked HPI 0090A

Replacement probes can be obtained by emailing:

If you are using a DSTREAM unit then no such probe is required. Connect to your target as normal.

You will need to ensure you have installed DSTREAM / RVI host software and firmware version 3.1 (or later) to debug targets using SWD.

When connecting to your target using SWD, you need to perform the following steps:

  1. Open the Debug Hardware Config / RVConfig window and connected to your DSTREAM/RVI unit, uncheck Use Adaptive Clock if detected and set the initial JTAG Clock Speed to 1MHz.

    RVI Image: SWD Auto Configure

  2. Click on the Advanced option in the left-hand panel of the Debug Hardware Config / RVConfig window

    2.1 Change the LVDS Debug Interface mode entry to SWD
    2.2 Check the box beside the Use SWJ Switching entry.

    RVI Image: SWD RVConfig Advanced

    Note: If you are using a Luminary Cortex-M3 based target, you will also need to check the Use deprecated SWJ Sequence entry.  If you do not check this, you will see Error V2801C (Vehicle): 0xXXXXXXXX: No connection to target when attempting to connect.

    The RVConfig window will change from using TDI and TDO to using a single SWDIO line.

    RVI Image: SWD RVConfig SWDIO

  3. If you are using an LVDS probe, once successfully connected to your target, the LVDS probe indicates that you are using SWD by illuminating the green LED on the top side of the LVDS probe.

  4. The next step is to provide details on your CoreSight system configuration. Please see the related FAQ: How do I configure and debug my CoreSight system using RVD/RVI?

Attachments: img18942.jpg , img18941.jpg , img18940.jpg

Article last edited on: 2011-11-04 15:58:57

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