SLVSJQ4 May   2026 TMF0020

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
    6. 5.6 Timing Requirements
    7. 5.7 Functional Tests
    8. 5.8 Typical Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1 20480-Bit FRAM
      2. 6.3.2 FRAM Status Memory
      3. 6.3.3 Address Registers and Transfer Status
      4. 6.3.4 Writing Data to the FRAM
      5. 6.3.5 TMF0020 Device ID
      6. 6.3.6 Bus Termination
    4. 6.4 Device Functional Modes
      1. 6.4.1 Test Procedures for Functional Tests
        1. 6.4.1.1 Multiple Target Configurations
    5. 6.5 Programming
      1. 6.5.1 Serial Communication
      2. 6.5.2 Initialization
      3. 6.5.3 ROM Commands
        1. 6.5.3.1 READ ROM Command [33h]
        2. 6.5.3.2 MATCH ROM Command [55h]
        3. 6.5.3.3 SKIP ROM Command [CCh]
        4. 6.5.3.4 SEARCH ROM Command [F0h]
        5. 6.5.3.5 RESUME Command [A5h]
        6. 6.5.3.6 OVERDRIVE SKIP ROM Command [3Ch]
        7. 6.5.3.7 OVERDRIVE MATCH ROM Command [69h]
      4. 6.5.4 Memory Function Commands
        1. 6.5.4.1 Write Scratchpad Command [0Fh]
        2. 6.5.4.2 Read Scratchpad Command [AAh]
        3. 6.5.4.3 Copy Scratchpad [55h]
        4. 6.5.4.4 Read Memory [F0h]
        5. 6.5.4.5 Extended Read Memory [A5h]
        6. 6.5.4.6 Memory Command Flow Charts
      5. 6.5.5 SDQ single-wire serial interface Signaling
        1. 6.5.5.1 RESET and PRESENCE PULSE
        2. 6.5.5.2 Write-Read-Time Slots
      6. 6.5.6 IDLE
      7. 6.5.7 CRC Generation
  8. 7 Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Application
      1. 7.2.1 Design Requirements
      2. 7.2.2 Detailed Design Procedure
      3. 7.2.3 Application Curves
    3. 7.3 Power Supply Recommendations
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
      2. 7.4.2 Layout Example
  9. 8 Device and Documentation Support
    1. 8.1 Receiving Notification of Documentation Updates
    2. 8.2 Support Resources
    3. 8.3 Trademarks
    4. 8.4 Electrostatic Discharge Caution
    5. 8.5 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information
    1. 10.1 Packaging Information
    2. 10.2 Tape and Reel Information

6.5.5 SDQ single-wire serial interface Signaling

The single wire communication does not have a reference clock, and adhering to stringent timing protocols to maintain the data integrity is critical. The timing protocol (compatible with 1-wire® protocol) consists of four types of signaling:

  1. Reset sequence with reset pulse and presence pulse
  2. Write-zero timing sequence
  3. Write-one timing sequence
  4. Read-data timing sequence

The host initiates the communication by pulling the SDQ single-wire serial interface line low, except for the presence pulse, which is initiated by the target devices on the SDQ single-wire serial interface bus. The target devices can communicate at two different speeds: standard and overdrive. The target device by default only communicates at standard speed unless the device is set into the Overdrive mode, in which case the target device responds to commands issued in the Overdrive timing (fast timing). All of the timing waveforms below are applicable to both Standard timing and Overdrive timing.

All SDQ single-wire serial interface signaling begins with initializing the device, followed by the host driving the bus low either to write a 1 or 0, or to begin the start frame for a bit read. Reset Sequence Timing Diagram shows the initialization timing, whereas Write-One Timing Diagram, Write-Zero Timing Diagram, and Read-Data Timing Diagram show that the host initiates each bit by driving the SDQ single-wire serial interface bus low for the start period, tW1L / tW0L / tRL. After the bit is initiated, either the host continues controlling the bus during a WRITE, or the target device controls the bus to transfer a 0 bit during a READ.