DisplayPort 1.4 Transmitter Compliance and Debug Solution

TekExpress DisplayPort 1.4 Transmitter Compliance Automation Software

Tektronix provides comprehensive solutions for engineers designing DisplayPort silicon for computer systems and embedded systems. This software validates the physical-layer compliance of DisplayPort devices against the DisplayPort 1.4 Compliance Test Specification.

The Tektronix Option DP14 application is compatible with Tektronix DPO/MSO 70000 DX/SX series oscilloscopes, designed to meet the challenges of next-generation Display standards like HDMI and DisplayPort.

Key Offerings

• Complete automated compliance testing: less than 7 hours for data rates up to HBR2, and less than 11 hours for data rates up to HBR3.
• Intelligent pattern recognition before test execution.
• Fixture de-embed feature: Use default filter files or create custom files with SDLA software for channel modeling and receiver equalization.
• Easy support for measurement repeatability.
• Customizable reports by Tests, Lanes, Data Rates, or Pass/Fail results.
• Timer pop-ups for zero user interaction during testing.
• Enhanced TekExpress reports with new measurement plots.
• Single application for Standard and Type-C DisplayPort testing.

Key Features

• 100% DisplayPort High Speed transmitter test coverage.
• Complete DUT automation for hands-free testing.
• User-friendly interface with single UI for DUT configuration.
• Optimized algorithms for improved accuracy.
• Optional signal validation to quickly detect anomalies.
• Reports available in mht, pdf, and csv formats for advanced data analysis.
• Supports Compliance (TekExpress) and Characterization (DPOJET) tests.
• DUT automation via SCPI-based Programmatic Interface (PI).
• Automation support and scripting with Iron Python for remote interface.
• Supports Manual and Automated test modes for Type-C and Standard DP.
• Stand-alone utility support for DPR-100 aux controller.
• Capture and save DUT waveforms for offline analysis.

DisplayPort 1.4 Compliance/Debug Solution

Solution Overview

A significant challenge in DisplayPort compliance testing is the long test times and the need for complete DUT automation. Engineers often spend considerable time monitoring test setups. The integration of DisplayPort with USB Type-C further complicates this.

The Tektronix DisplayPort Transmitter test solution addresses this by offering a test application with integrated Type-C and HBR3 data rate support. The DP12 software, combined with a DisplayPort Aux controller, automates DisplayPort physical layer source compliance testing for Standard and Type-C needs. The TekExpress solution integrates with the Unigraf DPR-100 reference sink, eliminating user interaction. Engineers can select tests and perform other tasks while tests execute.

The DP14 option supports transmitter compliance testing up to 8.1 Gbps (HBR3) as per the DisplayPort 1.4 specification. It also includes a utility for debugging the setup, developed for controlling the DPR-100 controller.

Simple Setup and Test Execution

Test setup and execution are straightforward with the DP1.4 automated software. Schematics for each test provide connection details. The TekExpress software offers a Graphical User Interface (GUI) and an intuitive workflow. Test system setup is simplified by viewing schematics with a single click.

DisplayPort Type-C Setup Overview

With the introduction of Type-C, DisplayPort extends its functionality as an alternate mode of USB over Type-C technology. This allows users to integrate display, data, and power needs into a single connector. The challenge lies in testing the same physical layer across three different standards for complete Type-C compliance.

For DisplayPort, functional differences exist between Standard and Type-C DUTs. The HPD (Hot Plug Detect) signal, required for a source DUT to transmit, changes from interrupt-based to message-based in Type-C. This is achieved by transitioning the Type-C DUT from its default USB mode to DisplayPort mode via PD messages over the CC (Configuration Channel) lines, as per the Power Delivery specification. This requires a USB PD controller. Once negotiated, a second controller (test mode controller) manages DUT configuration (data rates, patterns, amplitude, pre-emphasis, etc.).

The Tektronix Type-C setup automates these controllers using the TekExpress framework and integrates a Type-C fixture for complete 4-lane DUT automation using P7313SMA differential probes.

Diagram Description: A diagram illustrates the DisplayPort Type-C setup, showing connections between the USB, oscilloscope, RF switch, AUX control board with EPROM, and the DisplayPort cable to the test adapter.

For testing ML0 and ML3 signals (Pins A10-A11, B10-B11), connect recommended DC blocks at the test fixture output.

Diagram Description: A diagram shows a DisplayPort Type-C setup with a dongle, indicating connections for USB power, USB, and DisplayPort.

DisplayPort Transmitter Test Overview

DisplayPort sources (transmitters) require state control to transmit data patterns and signal properties according to the compliance test specification. Full measurement coverage requires the following properties and patterns:

• Bit rates: RBR, HBR, HBR2, and HBR3
• Data patterns: D10.2, PRBS7, COMPEYE, PLTPAT
• FFE (pre-emphasis): 0 dB, 3.5 dB, 6 dB, 9.5 dB
• Output levels: 400 mV, 600 mV, 800 mV, 1200 mV
• SSC (spread spectrum): On/Off

TekExpress Compliance Solution Overview

TekExpress provides automated test support for Standard and Type-C DisplayPort Compliance Testing. The advanced TekExpress DisplayPort application leverages the latest TekExpress 4.0 framework, optimizing testing by nearly three times.

Screenshot Description: A screenshot of the TekExpress Automated Test Solution interface for DisplayPort, showing setup information, DUT ID, date/time, device type, application version, framework version, execution mode, compliance mode, result, execution time, DUT automation method, connector type, CTS version, DPR100 version, and general comments.

Eye Diagram and Histogram Analysis

Diagram Description: An eye diagram plot showing signal integrity with dynamic mask generation, and bathtub and histogram plots for HBR2 data rate at TP3_EQ.

According to the specification, the eye diagram must adhere to mask limits:

• Eye diagram width is established at any passing location along 0mV.
• Eye diagram height (symmetric around 0mV) is established at any passing location between 0.375 to 0.625UI.
• The measured eye must be equal to or larger than the appropriate eye mask.

The TekExpress application uses the DPOJET analysis engine to generate a dynamic mask tailored to the acquired signal. It automatically adjusts the mask's position based on the eye opening along the horizontal axis. Vertical coordinates align with the eye mask location corresponding to the maximum amplitude level.

Compliance to Characterization Support

Tektronix offers the DisplayPort DPOJET essentials package, bundled with TekExpress, for characterizing DUTs and analyzing their behavior. This serves as an analysis tool when DUTs fail compliance tests or when deeper failure analysis is needed. All supported compliance tests requiring a single acquisition are included. Users can build automation scripts around these measurements to create custom test environments.

CSV Reporting for Data Analysis

The document mentions CSV reporting for data analysis.

Transmitter Eye Diagram Measurement

Screenshot Description: Screen captures illustrate how an adaptive mask is utilized in a DisplayPort Eye diagram measurement.

The DisplayPort DPOJET Essentials package can be enabled via the Oscilloscope's Analyze menu. This measurement library aids in characterizing silicon and debugging failures. If compliance tests fail, the DPOJET DisplayPort measurement library allows for in-depth analysis of issues like eye diagram mask hits and the relationship between pre-emphasis levels and voltage swing tests for root cause analysis. The solution also provides flexibility in configuring measurements, making on-the-fly changes, and running tests in single-shot or free-run modes.

Introducing DPR-100 Utility

This utility verifies setup connections and DUT behavior before running compliance tests. It is bundled with the TekExpress DP 1.4 installer and controls the DPR-100 Aux controller to adjust DUT settings like data rates, patterns, and levels. It also helps control the PD controller for DisplayPort Type-C setups.

Diagram Description: A diagram shows the DPR-100 utility setup, including connections for USB power, USB, oscilloscope, RF switch, and AUX control board with EPROM for setting up DPCD.

SDLA Features

SDLA (Serial Data Link Analysis) enables probing and visualizing data at required locations using virtual probing. It can remove (de-embed) the effects of cables, probes, and fixtures for more accurate results. SDLA can embed user-defined channel models to simulate signals at the link's end. It also supports opening closed eyes using receiver equalization techniques like CTLE (Continuous Time Linear Equalizer) and DFE (Decision Feedback Equalizer).

SDLA also provides advanced analysis and modeling capabilities for Forward Equalization (FFE). Users can view and measure multiple test points using DPOJET Jitter and Eye analysis, including frequency and time domain plots, and verify S-parameters and test point transfer functions.

Switch Matrix Support

Switch Matrix for DisplayPort (SWX-DP) is a software solution integrated with TekExpress DisplayPort. It simplifies configuring and setting up automated multi-lane testing using RF switches. Users can perform both differential and single-ended tests as per DP 1.2/1.4 specifications without changing connections, significantly reducing test times.

Key features of SWX-DP include:

• Auto-detects Keithley switches on the GPIB/LAN interface.
• De-embeds using filter files with multiple options (per relay, per input, etc.).
• Operates with TekExpress and DPOJET (Debug Mode).
• Saves/recalls switch configurations.
• Provides graphical view with print option for hardware wiring.
• Integrates graphically with TekExpress reports.
• Includes built-in error handling for easy and error-free configuration.
• Supports custom input labels (Lane, Port, etc.) via XML file edits.
• Offers a programmatic interface for scripting and integration into automation environments.

Proposed Measurements

List of supported measurements as per DP 1.4a Standard/Type-C CTS:

• 3.1 Eye-diagram Testing
• 3.2 Non Pre-Emphasis Level Verification Testing
• 3.3 Pre-Emphasis Level Verification Testing
• 3.3 HBR2/HBR3 Level and Equalization Verification Testing
• 3.4 Inter Pair Skew Test
• 3.5 Intra-Pair Skew Test
• 3.10 AC Common Mode Noise
• 3.11 Non ISI Jitter Measurements
• 3.12.1 Total Jitter (TJ) and Deterministic (DJ) Measurements
• 3.12.2 Random Jitter (RJ) Measurements
• 3.14 Main Link Frequency Compliance
• 3.15 Spread Spectrum Modulation Frequency
• 3.16 Spread Spectrum Modulation Deviation
• 3.17 dF/dt Spread Spectrum Deviation HF Variation
• 3.18 Dual mode TMDS Clock
• 3.19 Dual-mode EYE Diagram Testing
• 8.1 AUX Manchester Channel Eye Test
• 8.2 AUX Manchester Channel Sensitivity Test
• 8.5 AUX Inrush Test
• 9.2 AUX Slew Rate

General Characteristics

Physical characteristics

Ordering Information

Software Ordering Information

DP1.4 software can be ordered as an upgrade option for a Tektronix oscilloscope or with a new oscilloscope. Refer to www.tektronix.com/displayport for detailed product configuration on Source testing.

Recommended Fixture and Accessories for DisplayPort Testing

Prerequisite Host System Software Requirements for DisplayPort Testing

Contact Information

For more information about DisplayPort testing, visit our website www.tek.com/displayport.

Tektronix maintains a comprehensive collection of application notes, technical briefs, and other resources. Please visit www.tek.com.

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