SPRACU8B August   2021  – January 2023 AM68 , AM68 , AM68A , AM68A , AM69 , AM69 , AM69A , AM69A , DRA821U , DRA821U , DRA829V , DRA829V , TDA4VM , TDA4VM

 

  1.   Abstract
  2.   Trademarks
  3. 1Introduction
    1. 1.1 Features
      1. 1.1.1 Supported Features (version 0.10.0)
      2. 1.1.2 Unsupported Features (version 0.10.0)
    2. 1.2 Spreadsheet Overview
      1. 1.2.1 Input Worksheets
      2. 1.2.2 Output Worksheets
      3. 1.2.3 Other Worksheets
    3. 1.3 Default SDK Configurations
  4. 2Customizing DDR Configuration
    1. 2.1 Config Worksheet
      1. 2.1.1 System Configuration
      2. 2.1.2 Memory Burst Configuration
    2. 2.2 DRAMTiming Worksheet
      1. 2.2.1 Latency Parameters
      2. 2.2.2 Non-Latency Parameters
    3. 2.3 IO Control Worksheet
      1. 2.3.1 Determining IO Settings
      2. 2.3.2 Processor/DDR Controller IO
      3. 2.3.3 DRAM I/O
  5. 3Software Considerations
    1. 3.1 Updating U-Boot
      1. 3.1.1 Updating DDR Register Settings
      2. 3.1.2 Updating Source to Set Available Memory Size
    2. 3.2 Updating RTOS PDK
      1. 3.2.1 Updating DDR Register Settings
  6. 4Troubleshoot Guide
    1. 4.1 Topics/Issues
      1. 4.1.1 Topic 1
      2. 4.1.2 Topic 2
      3. 4.1.3 Topic 3
  7. 5References
  8.   Revision History

2.3.1 Determining IO Settings

The optimal IO settings may vary from system to system due to board layout and routing differences, even if the systems utilize the same processor and DDR. Thus, it is important to perform simulations as described in the Jacinto7 LPDDR4 Board Design and Layout Guidelines and analyze the waveforms to identify the settings which give the best margins. This procedure may require several iterations of simulations before discovering the best settings. As a general starting point, you can select drive strength and termination settings to match the trace impedance on the PCB. For more information on performing the simulations, see the Jacinto7 LPDDR4 Board Design and Layout Guidelines.