SPMU381A April   2026  – August 2026 TPS25752A

 

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  2. 1Read This First
    1. 1.1 Notational Conventions
    2. 1.2 Glossary
    3. 1.3 Related Documents
    4. 1.4 Support Resources
    5. 1.5 Trademarks
  3. 2Introduction
    1. 2.1 Purpose and Scope
  4. 3PD Controller Host Interface Description
    1. 3.1 Overview
    2. 3.2 Register and Field Notation
  5. 4Unique Address Interface
    1. 4.1 Unique Address Interface Protocol
  6. 5PD Controller Policy Modes
    1. 5.1 Overview
    2. 5.2 Source Policy Mode
  7. 6Register Overview
    1. 6.1 TPS25752A Registers
  8. 74CC Task Detailed Descriptions
    1. 7.1 Overview
    2. 7.2 CPU Control Tasks
      1. 7.2.1 'Gaid' - Return to Normal Operation
      2. 7.2.2 'GAID' - Cold Reset Request
    3. 7.3 PD Message Tasks
      1. 7.3.1 'SWDF' - PD DR_Swap to DFP
      2. 7.3.2 'SWUF' - PD DR_Swap to UFP
      3. 7.3.3 'GSkC' - PD Get Sink Capabilities
      4. 7.3.4 'SSrC' - PD Send Source Capabilities
      5. 7.3.5 'GPPI' - PD Get Port Partner Information
      6. 7.3.6 'MBRd' - Message Buffer Read
    4. 7.4 Patch Bundle Update Tasks
      1. 7.4.1 'PBMs' - Start Patch Burst Mode Download Sequence
      2. 7.4.2 'PBMc' - Patch Burst Mode Download Complete
      3. 7.4.3 'PBMe' - End Patch Burst Mode Download Sequence
      4. 7.4.4 'FLrd' - Flash Memory Read
      5. 7.4.5 'FLad' - Flash Memory Write Start Address
      6. 7.4.6 'FLwd' - Flash Memory Write
      7. 7.4.7 'FLvy' - Flash Memory Verify
    5. 7.5 System Tasks
      1. 7.5.1 'I2Cr' - I2C Read Transaction
      2. 7.5.2 'I2Cw' - I2C Write Transaction
      3. 7.5.3 'GPsh' - set GPIO high
      4. 7.5.4 'GPsl' - set GPIO low
  9. 8User Reference
    1. 8.1 PD Controller Application Customization
    2. 8.2 Loading a Patch Bundle
    3. 8.3 Liquid Detection Registers
    4. 8.4 GPIO Events
  10. 9Revision History

7.3.6 'MBRd' - Message Buffer Read

Table 7-9 'MBRd' - Read from PD message buffer.
DescriptionThe MBRd Task instructs the PD Controller to read data from the extended message buffer previously received from the Port Partner.
INPUT DATAXBitNameDescription
23ReservedReserved (Write as 0).
22UnlockRxBufferThis input controls whether or not the PD controller unlocks its internal buffer after this Task is completed. It is recommended to unlock the internal buffer as soon as possible to make room for other incoming messages. It is important that the host only set this bit to 1 after it has received an alert that the Rx Buffer is locked (that is INT_EVENTx.MBRdBufferReady asserted).
0bDo not clear the internal buffer, another 'MBRd' Task can be used later.
1bClear the internal buffer after this Task completes and the requested data is in the DATAx register.
21:16DataSizeNumber of data bytes to be read in from the message buffer. Up to 62 bytes can be read at after.
15:0BuffOffsetBuffer Offset. Values 0 to 259 are possible.
OUTPUT DATAXBitNameDescription
511:16DataByte1First Byte of data read at BuffOffset.
15:0MessageSizeSize of message in bytes.
Task CompletionThe MBRd Task completes after buffer data of DataSize at BuffOffset has been read from the message buffer.
Side EffectsNone
Additional InformationThis Task is required for the host to obtain the information from the response due to the usage of the 'GPPI' Task . The PD controller has a single buffer per port that is shared for these messages.