DisplayPort 2.1 Compliance and Debug Solution

Overview

Tektronix provides the most comprehensive solution to serve the need of engineers designing DisplayPort silicon for computer systems and embedded systems, as well as for those who are validating the physical-layer compliance of DisplayPort devices as per the DisplayPort 2.1 Compliance Test Specification (CTS). The Tektronix TekExpress DisplayPort 2.1 Compliance/debug solution help the customers to test their DP2.1 DUTs. The Tektronix application is compatible with Tektronix 7 Series DPO and DPO/MSO 70000 DX/SX Series oscilloscopes that are designed to meet the challenges of the next generation of display standards such as HDMI and DisplayPort.

Key features

• Complete compliance testing of data rates UHBR10, UHBR13.5, and UHBR20 for DP2.1 Source devices (Enhanced DP, mDP, and Type-C connectors)

• Supports preset optimization feature to find out separate optimal presets for TP2 and TP3_EQ Test points for individual data rates

• Supports TX Preset Equalization Tests for all data rates

• Supports normative and informative measurements that are mentioned in DisplayPort 2.1 CTS

• Optimized algorithms to execute tests with improved accuracy

• Analyze multiple data rates and multiple presets at TP2 and TP3 EQ test points for multiple lanes on one go

• Supports DUT toggle automation using Unigraf UCD-323 device

• Support P7625 and P7633 differential probes

• Fixture De-embedding in differential and single-ended mode by creating a custom filter file using SDLA software to leverage the channel modelling and receiver equalization functionality

• Support DP2.1 Compliance test execution on best preset as well as all selected preset

• Supports signal validation option to detect anomalies in the signal before analysis

• Supports offline analysis of the saved waveforms in Pre-recorded mode

• Provides a consolidated report for all tests in .mht, .pdf, and .csv formats.

Solution overview

TekExpress DisplayPort 2.1 supports 16 presets for UHBR data rates. It allows you to choose the optimal preset and run the Signal Quality test on it. The DisplayPort 2.1 solution provides flexibility to select different presets for different test points for available data rates. If optimal preset is unknown then the DisplayPort solution allows you to select multiple presets to find the optimal preset from the selected presets and run the Signal Quality test on the optimal preset.

The DisplayPort solution provide Signal Quality run on all presets. It allows you to run a subset of Signal Quality measurements. By default DisplayPort cables (DP40 and DP80) are configured for testing but different cable models can be selected in Advanced mode.

Preset selection panel for signal quality measurements

DisplayPort 2.1 transmitter test overview

DisplayPort sources (transmitters) have state control requirements in order to transmit the data patterns and signal properties required to demonstrate conformance as per the compliance test specification. The following properties and patterns need to be transmitted for full measurement coverage:

• Bit rates: UHBR10, UHBR13.5, and UHBR20

• Data patterns: PRBS15, PRBS31, and SQ128

• Preset: 16 presets as defined

• Output levels: 800 mV

• SSC (spread spectrum): On/Off

Compliance to characterization support

Tektronix offers DisplayPort 2.0 DPOJET essentials package which comes bundled with TekExpress DisplayPort 2.1 Compliance and Debug solution that can be used to characterize a DUT and analyze its finer behavior. It serves as an analysis tool when the DUT fails any portion of the compliance tests or you want to take a deeper look into the failures. All the compliance tests which are supported in the application and requires a single acquisition are supported in this package. You can build automation scripts around these measurements to setup a custom test environment. The DisplayPort 2.0 DPOJET solution also supports all measurements for lower data rates such as RBR, HBR, HBR2, and HBR3.

You can enable this package by running DisplayPort 2.0 from the Oscilloscope → Analyze menu. The DisplayPort 2.0 DPOJET measurement library helps in characterizing the silicon. Other advantage of this library is the ability to debug the measurements in case of failures. If any of the tests fail during compliance testing, you can use the DPOJET DisplayPort measurement library for a deeper analysis of the failures such as eye diagram mask hit failures and look at relation between pre-emphasis level vs voltage swing tests to identify the root cause of failure. The solution also gives users the flexibility to configure measurements with different settings, make configuration changes in existing measurements on the fly, and run tests in single-shot or free-run repetitive modes.

DisplayPort 2.0 DPOJET solution comes with setup files. All measurements corresponding to a data rate and a particular pattern are clubbed in a single setup file. Setup files for lower data rates such as RBR, HBR, HBR2, and HBR3 are also included. Setup file helps to avoid any manual mistakes while configuring a measurement. This ensures that a non-expert user can also use the debug solution and validate the results.

DPOJET DisplayPort 2.0 standard dropdown

DPOJET CIO standard dropdown

SDLA features

SDLA provides the following features:

• Enables the user to probe and visualize data at the required location (de-embed / embed) using virtual probing through test points.

• Removes (de-embed) the effects of the cables, probes, and fixtures to get more accurate measurement results.

• Embeds user defined channel models to simulate the signal at the end of the link.

• Opens a closed eye using receiver equalization, Continuous Time Linear Equalizer (CTLE), Decision Feedback (DFE), or Feed Forward Equalization (FFE).

• Provides advanced analysis and modeling capabilities.

• View and measure multiple test points using DPOJET jitter and eye analysis comprehensive frequency and time domain plots.

• Enables quick verification of S-parameters and test point transfer functions.

For DisplayPort 2.1, SDLA provides the flexibility of choosing the optimal CTLE. To calculate optimal CTLE based on Eye Area, SDLA selects the appropriate DisplayPort standard from the CTLE dropdown menu and runs the configuration from 0 dB to -9 dB. Optimal CTLE waveforms gets loaded on the oscilloscope and can be configured.

RX setup in SDLA