Getting Started with DbC

Overview

The Direct Connect Interface (DCI) is an emerging transport technology for closed-chassis debug access. The primary purpose of DCI is to allow existing functional I/O (e.g., a USB port) to be used for debug of the system and/or silicon, and to gain access to trace/debug features in the silicon. DCI DbC allows target debug with a single USB connection between the host computer and the target. No debug probe is required.  This document explains the steps necessary to get DbC up and running.

There are two forms of DCI DbC, one that uses USB 2.0 (DCI DbC2), and one that uses USB 3.0 (DCI DbC3). For run control purposes the speed of either is sufficient.  DCI DbC2 has the advantage of allowing debug through resets and power cycles.  Throughout the rest of this document DbC will be used to indicate DCI DbC2.

Preparing the Firmware image

A firmware image needs to be modified to configure the silicon (PCH) for the appropriate USB port which will be used for DbC. This is achieved by using the Intel® FIT tool and the firmware image. The default setting of the FIT tool is to not enable any ports for DbC.

There are two ways to modify a firmware image. Automatically by an XML during the build process, or manually by loading the firmware image into the FIT tool after the build process has completed. This Getting Started guide will concentrate on using the manual method for modifying an existing image.

The end user will need access to the target user guide or schematics to look up the connectivity of the physical USB port from the silicon  to the required USB connector on the target. For example, a target could have a rear USB connector, J1, which is wired to the PCH USB2.0 Port 5. In this case, the FIT tool is configured to use USB2.0 Port 5

NOTE: It should be noted that the FIT tool version used to enable DbC should be the same version (or newer) as the existing firmware image.

To enable DbC for a specified USB2.0 port:

1. Open the Intel FIT tool

2. Load an existing firmware image (File->Open)

3. The FIT tool will create a log view within the GUI. The details of the version used to create the firmware image will be displayed:

FIT version used to build the image: 12.0.0.1051

4. Ensure the FIT tool used to enable DbC is a version that is the same (or greater) than the version stated in (3)

5. In the left hand tree view, scroll down to the Debug section, and click

6. In the right-hand tree view, scroll down to the Direct Connect Interface Configuration section

a. Ensure that Direct Connect Interface (DCI) Enabled is set to 'Yes'

7. In the right-hand tree view, scroll down to the Early USB2 DBC over Type-A Configuration section

a. Ensure that USB2 DbC port Enable is set to the USB port required for the physical connector on the target to be used for DbC. For example, ’USB2 Port 1’

8. Create the new image (Build->Build Image or CTRL-B)

a. If prompted that Boot Guard is disabled on the platform, then click 'Yes' to accept and proceed

9. A new firmware image called 'outimage.bin' will be created. Rename this image appropriately, and program onto the target.

Enabling DbC in BIOS

The Debug Consent setting in the BIOS must be set to enable DbC debug.

1. Type 'exit' at the EFI prompt to enter BIOS setup (or press F8 if booting to an OS).

2. Select Intel Advanced Menu

3. Select Debug Settings

4. Change the Platform Debug Consent setting to either 'USB2 DbC' or 'DCI OOB+[DbC]'.

5. Save the settings and exit.

Note: These steps may vary between different versions of BIOS.

Connecting the Host to the Target

There are two types of USB cables that can be used:

1. USB3.x Type-A to Type-A

2. USB3.x Type-A to Type-C.

Caution:  These are not standard USB cables.  They are special cables with no VBus connection.  Using a standard cable may damage the host computer and/or the target.

Which cable you need depends on whether you enable DbC (in the BIOS image) on a Type-A or Type-C connector.

These cables are available at Intel’s Design-In Store (https://designintools.intel.com).  Following are the part numbers. Intel recommends the 1 Meter cables, but in most instances the 1.8 Meter cables work fine.

Connect the Type-A end of the cable to any USB2 or USB3 connector on the host computer.  Connect the other end to whichever USB port on the target has DbC enabled.

Installing the Intel DCI Driver

The Intel DCI driver is installed automatically when SourcePoint is installed.  When active (the host is connected to a target with DbC enabled), the following driver entry will be present in Device Manager:

 

Testing the Connection

Included in the SourcePoint installation is a DbC debug utility that can be used to determine if a valid DbC connection has been made. It can be found in the same folder as sp.exe and is called DbCStatus.exe.

1. Power down the target.

2. Connect the USB cable between the host and target.

3. Start the DbC Indicator program.   It should show red for no connection:

 

 

 

4. Power on the target.

5. The DbC Indicator program should now show green for a USB2 connection (you’ll also hear the Windows USB device connected sound).

 

 

6. Close the DbC indicator program.

Connecting with SourcePoint

SourcePoint behaves the same whether it’s connected to a debug probe (e.g., ECM-XDP3e), or directly to the target via DbC.  The only difference is the emulator connection type.  With a debug probe, you create a TCP/IP or USB connection, with DbC you create a DCI connection type.

1. Install SourcePoint.

2. Start SourcePoint.

3. The New Project Wizard will start.  

a. Specify the connection type as 'DCI’.

b. Point to the target configuration file for the type of target you’re using.