SDAA519 September   2026 DRA821U-Q1 , TDA4AEN-Q1 , TDA4AH-Q1 , TDA4AL-Q1 , TDA4AP-Q1 , TDA4APE-Q1 , TDA4VE-Q1 , TDA4VEN-Q1 , TDA4VH-Q1 , TDA4VL-Q1 , TDA4VP-Q1 , TDA4VPE-Q1

 

  1.   1
  2.    Abstract
  3.    Trademarks
  4. 1  Introduction
  5. 2  Acronyms and Definitions
  6. 3  USB 2.0 High Speed TX Compliance: Theory of Operation
    1. 3.1 USB 2.0 High Speed Signaling Overview
    2. 3.2 xHCI Port Test Control and Compliance Mode Entry
    3. 3.3 Eye Diagram Compliance
  7. 4  Register Reference
    1. 4.1 xHCI PORTSC — Port Status and Control Register
    2. 4.2 PORTPMSC Bit-Field Description (USB 2.0 — xHCI Spec)
    3. 4.3 Compliance Write Value Decode: 0x40000000
    4. 4.4 USB2 PHY TX Amplitude Register — USB2SS_PHY2_AFE_TX_REG1
  8. 5 Compliance Procedure: TDA4VEN / J722S / TDA4AEN
    1. 5.1 Hardware Requirements
    2. 5.2 Software Requirements
    3. 5.3 Hardware Setup
    4. 5.4 Physical Connections
    5. 5.5 Device Tree Source (DTS) Modification for USB0
    6. 5.6 Step 1: Verify EVM Boot and Console
    7. 5.7 Step 2: Write xHCI Registers to Enable HS Test Packet Mode
    8. 5.8 Step 3: Capture the HS Test Packet Waveform on the Oscilloscope
  9. 6 USB-IF Electrical Analysis Tool: Post-Processing Procedure
  10. 7  Adjusting the HS TX Amplitude
    1. 7.1 TX Amplitude Adjustment Procedure
  11. 8 Compliance Procedure: J7200/J784S4/J721S2/J742S2
  12. 9 Troubleshooting
  13. 10Summary
  14. 11References

1 Introduction

USB 2.0 High Speed (HS) electrical compliance testing verifies that a device meets the eye-diagram, output amplitude, and data-rate requirements defined in the USB 2.0 Specification (Section 7.1.20) and the USB-IF Compliance Test Specification (CTS). The test evaluates the quality of the differential transmit signal (TX) at the host port, measured as the eye opening against the inner and outer mask specification.

This application note focuses on the Host Transmit (TX) compliance path for Jacinto SoCs implementing the xHCI host controller with a USB 2.0 UTMI+ PHY. The procedure is applicable to TDA4VEN, J722S, and TDA4AEN devices. Unlike USB 3.0 Host compliance (described in the A Guide to USB3.1 Gen1 SuperSpeed Host Transmit Electrical Compliance application note), which requires a SERDES link training state machine (LTSSM), USB 2.0 compliance mode is entered by programming the Port Test Control field in the xHCI PORTSC register and optionally adjusting the PHY analog front-end registers for TX amplitude optimization.

A practical consideration for TDA4VEN(1) is the signal integrity impact of the USB multiplexer and Type-C ICs present on the EVM board. The additional passive and active components in the signal path degrade the eye diagram, causing the inner eye mask violation at the oscilloscope input. For best compliance results, routing the USB2.0 HS signals to a type-A connector without the intermediate ICs or Type-C connectors is recommended.

1. TDA4VEN is used thorughout the application note but equally applies to TDA4AEN