SNLS779A July   2025  – November 2025 DP83TC815-Q1

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison Table
  6. 5 Pin Configuration and Functions
    1. 5.1 Pin Power Domain
    2. 5.2 Pin States
    3. 5.3 Pin Multiplexing
  7. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Timing Requirements
    7. 6.7 Timing Diagrams
    8. 6.8 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 IEEE802.1AS Features
        1. 7.3.1.1 PTP Clock Configuration
          1. 7.3.1.1.1 PTP Reference Clock
          2. 7.3.1.1.2 PTP Synchronized Clock (Wall Clock)
            1. 7.3.1.1.2.1 PTP Time Read or Write
            2. 7.3.1.1.2.2 PTP Clock Initialization
            3. 7.3.1.1.2.3 PTP Clock Adjustment
            4. 7.3.1.1.2.4 PTP Clock Output
              1. 7.3.1.1.2.4.1 One Pulse Per Second (PPS) Output
          3. 7.3.1.1.3 PTP Time Registers
        2. 7.3.1.2 Packet Timestamps
          1. 7.3.1.2.1 Transmit (Egress) Packet Parser and Timestamp
          2. 7.3.1.2.2 Receive (ingress) Packet Parser and Timestamp
          3. 7.3.1.2.3 PTP Transmit and Receive Timestamp Registers
        3. 7.3.1.3 Event Triggering and Timestamping
          1. 7.3.1.3.1 Event Triggering (Output)
            1. 7.3.1.3.1.1 Trigger Initialization
          2. 7.3.1.3.2 Event Timestamp (Input)
            1. 7.3.1.3.2.1 Timestamp Storage and Reading
          3. 7.3.1.3.3 Event Capture and Output Trigger Registers
        4. 7.3.1.4 PTP Interrupts
        5. 7.3.1.5 PTP I/O Configuration
      2. 7.3.2 TC10 Sleep Wake-up
        1. 7.3.2.1 Functions of the PHY for TC10 Support
          1. 7.3.2.1.1 Transition from Sleep to Wake-up Mode
            1. 7.3.2.1.1.1 Local Wake Detection
            2. 7.3.2.1.1.2 WUP Transmission and Reception
          2. 7.3.2.1.2 Wake Forwarding
          3. 7.3.2.1.3 Transition to Sleep - Sleep Negotiation
            1. 7.3.2.1.3.1 Sleep Ack
            2. 7.3.2.1.3.2 Sleep Request
            3. 7.3.2.1.3.3 Sleep Silent
            4. 7.3.2.1.3.4 Sleep Fail
            5. 7.3.2.1.3.5 Sleep
            6. 7.3.2.1.3.6 Force Sleep
        2. 7.3.2.2 Power Supply Networks for Sleep Applications
        3. 7.3.2.3 Configuration for Non-TC10 Applications
        4. 7.3.2.4 Miscellaneous Sleep Features
        5. 7.3.2.5 Fast Wake-up
      3. 7.3.3 PPM Monitor
      4. 7.3.4 Clock Dithering
      5. 7.3.5 Output Slew Control
      6. 7.3.6 Diagnostic Tool Kit
        1. 7.3.6.1 Signal Quality Indicator
        2. 7.3.6.2 Electrostatic Discharge Sensing
        3. 7.3.6.3 Time Domain Reflectometry
        4. 7.3.6.4 Voltage Sensing
        5. 7.3.6.5 Temperature Sensing
      7. 7.3.7 BIST and Loopback Modes
        1. 7.3.7.1 Data Generator and Checker
        2. 7.3.7.2 xMII Loopback
        3. 7.3.7.3 PCS Loopback
        4. 7.3.7.4 Digital Loopback
        5. 7.3.7.5 Analog Loopback
        6. 7.3.7.6 Reverse Loopback
      8. 7.3.8 Compliance Test Modes
        1. 7.3.8.1 Test Mode 1
        2. 7.3.8.2 Test Mode 2
        3. 7.3.8.3 Test Mode 4
        4. 7.3.8.4 Test Mode 5
    4. 7.4 Device Functional Modes
      1. 7.4.1 Power Modes
        1. 7.4.1.1 Power Down
        2. 7.4.1.2 Reset
        3. 7.4.1.3 Standby
        4. 7.4.1.4 Normal
        5. 7.4.1.5 Sleep
      2. 7.4.2 Media Dependent Interface
        1. 7.4.2.1 100BASE-T1 Leader and 100BASE-T1 Follower Configuration
        2. 7.4.2.2 Auto-Polarity Detection and Correction
        3. 7.4.2.3 Jabber Detection
        4. 7.4.2.4 Interleave Detection
      3. 7.4.3 MAC Interfaces
        1. 7.4.3.1 Media Independent Interface
        2. 7.4.3.2 Reduced Media Independent Interface
        3. 7.4.3.3 Reduced Gigabit Media Independent Interface
        4. 7.4.3.4 Serial Gigabit Media Independent Interface
      4. 7.4.4 Serial Management Interface
        1. 7.4.4.1 Extended Register Space Access
        2. 7.4.4.2 Write Operation (No Post Increment)
        3. 7.4.4.3 Read Operation (No Post Increment)
        4. 7.4.4.4 Write Operation (Post Increment)
        5. 7.4.4.5 Read Operation (Post Increment)
    5. 7.5 Programming
      1. 7.5.1 Strap Configuration
        1. 7.5.1.1 LED Configuration
  9. 8 Register Maps
    1. 8.1 Register Access Summary
    2. 8.2 DP83TC815 Registers
  10. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 Design Requirements
        1. 9.2.1.1 Physical Medium Attachment
          1. 9.2.1.1.1 Common-Mode Choke Recommendations
      2. 9.2.2 Detailed Design Procedure
      3. 9.2.3 Application Curves
    3. 9.3 Power Supply Recommendations
    4. 9.4 Layout
      1. 9.4.1 Layout Guidelines
        1. 9.4.1.1 Signal Traces
        2. 9.4.1.2 Return Path
        3. 9.4.1.3 Metal Pour
        4. 9.4.1.4 PCB Layer Stacking
      2. 9.4.2 Layout Example
  11. 10Device and Documentation Support
    1. 10.1 Device Support
      1. 10.1.1 Third-Party Products Disclaimer
    2. 10.2 Receiving Notification of Documentation Updates
    3. 10.3 Support Resources
    4. 10.4 Trademarks
    5. 10.5 Electrostatic Discharge Caution
    6. 10.6 Glossary
  12. 11Revision History
  13. 12Mechanical, Packaging, and Orderable Information
7.3.1.1.2.3 PTP Clock Adjustment

This section describes the available options to update the Clock time value. The DP83TC815-Q1 provides several mechanisms for updating the IEEE802.1AS clock based on the results of the synchronization protocol:

  • Directly Read/Writable (Directly Setting or Reading the Time)
  • Adjustable by Add/Subtract (Step-Time Adjustment)
  • Frequency Scalable (Continuous Time Adjustment)
  • Temporary Frequency Control (Temporary Time Adjustment)

Directly Read/Writable - Directly setting the system time clock to a value is accomplished by setting a new time in the clock registers (PTP_TDR). Initial setting of the clock/timer can require a direct write of a time value.

Adjustable by Add/Subtract - Time can also be adjusted by adding/subtracting a value to the present time value. For adding a value, the value has to be written to PTP_TDR register. For subtracting a value, the 32-bit 2’s complement representations of both seconds and nanoseconds fields can be written to PTP_TDR register. To add/subtract the following registers have to be written in the same order

  1. Write Clock_time_ns[15:0] to PTP_TDR
  2. Write Clock_time_ns[31:16] to PTP_TDR
  3. Write Clock_time_sec[15:0] to PTP_TDR
  4. Write Clock_time_sec[31:16] to PTP_TDR
  5. Write to PTP_CTL with the 'Step PTP Clock' bit set

Frequency Scalable- The system can be set up to perform continuous time adjustment to the IEEE802.1AS PTP clock. Frequency (clock/timer rate) can be adjusted via register control to match the frequency of the leader. This is also called Permanent Rate Adjustment. The clock can be programmed to operate at an adjusted frequency value by programming a rate adjustment value. The rate adjustment allows for correction on the order of 2-32 ns per reference clock cycle.

  • Rate Adjustment - The clock can be programmed to operate at an adjusted frequency value by programming a rate adjustment value. The rate adjustment allows for correction on the order of 2-32 ns per reference clock cycle. The frequency adjustment allows the clock to correct the offset over time, avoiding any potential side-effects caused by a step adjustment in the time value.

Temporary Frequency (Time) Control : Allows time correction by running at a modified frequency for a period of time. This is also called Temporary Rate Adjustment. The clock can be programmed to operate at a temporary adjusted frequency value by programming a rate adjustment value and duration. The rate adjustment allows for correction on the order of 2-32 ns per reference clock cycle. The frequency adjustment allows the clock to correct the offset over time, avoiding any potential side-effects caused by a step adjustment in the time value. The clock can also be programmed to perform a temporary adjusted frequency value by including a rate adjustment duration.

Several mechanisms can be used to update the PHY’s IEEE802.1AS clock, based on the results of the synchronization protocol. The method used to update the clock value can depend on the difference in the time values. For example, at the initial synchronization attempt, the clocks can be very far apart, and therefore require a Step Adjustment or a Direct Time Set. Later, when clocks are very close in value, the Temporary Rate Adjustment method can be the best option.