SLLSF93A June   2019  – January 2025 TUSB8042A

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Variants
    1. 4.1 Device Version Comparison
  6. 5 Pin Configuration and Functions
  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. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Battery Charging Features
      2. 7.3.2 USB Power Management
      3. 7.3.3 One-Time Programmable (OTP) Configuration
      4. 7.3.4 Clock Generation
      5. 7.3.5 Crystal Requirements
      6. 7.3.6 Input Clock Requirements
      7. 7.3.7 Power-Up and Reset
    4. 7.4 Device Functional Modes
      1. 7.4.1 External Configuration Interface
      2. 7.4.2 I2C EEPROM Operation
      3. 7.4.3 Port Configuration
      4. 7.4.4 SMBus Target Operation
  9. 8 Register Maps
    1. 8.1  Configuration Registers
    2. 8.2  ROM Signature Register
    3. 8.3  Vendor ID LSB Register
    4. 8.4  Vendor ID MSB Register
    5. 8.5  Product ID LSB Register
    6. 8.6  Product ID MSB Register
    7. 8.7  Device Configuration Register
    8. 8.8  Battery Charging Support Register
    9. 8.9  Device Removable Configuration Register
    10. 8.10 Port Used Configuration Register
    11. 8.11 Device Configuration Register 2
    12. 8.12 USB 2.0 Port Polarity Control Register
    13. 8.13 UUID Registers
    14. 8.14 Language ID LSB Register
    15. 8.15 Language ID MSB Register
    16. 8.16 Serial Number String Length Register
    17. 8.17 Manufacturer String Length Register
    18. 8.18 Product String Length Register
    19. 8.19 Device Configuration Register 3
    20. 8.20 USB 2.0 Only Port Register
    21. 8.21 Serial Number String Registers
    22. 8.22 Manufacturer String Registers
    23. 8.23 Product String Registers
    24. 8.24 Additional Feature Configuration Register
    25. 8.25 SMBus Device Status and Command Register
  10. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Discrete USB Hub Product
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
          1. 9.2.1.2.1 Upstream Port Implementation
          2. 9.2.1.2.2 Downstream Port 1 Implementation
          3. 9.2.1.2.3 Downstream Port 2 Implementation
          4. 9.2.1.2.4 Downstream Port 3 Implementation
          5. 9.2.1.2.5 Downstream Port 4 Implementation
          6. 9.2.1.2.6 VBUS Power Switch Implementation
          7. 9.2.1.2.7 Clock, Reset, and Misc
          8. 9.2.1.2.8 TUSB8042A Power Implementation
        3. 9.2.1.3 Application Curves
    3. 9.3 Power Supply Recommendations
      1. 9.3.1 TUSB8042A Power Supply
      2. 9.3.2 Downstream Port Power
      3. 9.3.3 Ground
    4. 9.4 Layout
      1. 9.4.1 Layout Guidelines
        1. 9.4.1.1 Placement
        2. 9.4.1.2 Package Specific
        3. 9.4.1.3 Differential Pairs
      2. 9.4.2 Layout Examples
        1. 9.4.2.1 Upstream Port
        2. 9.4.2.2 Downstream Port
  11. 10Device and Documentation Support
    1. 10.1 Documentation Support
      1. 10.1.1 Related Documentation
    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

8.9 Device Removable Configuration Register

Figure 8-8 Register Offset 7h
Bit No.76543210
Reset State0000XXXX
Table 8-9 Bit Descriptions – Device Removable Configuration Register
BitFieldTypeDescription
7customRmblRWCustom Removable. This bit controls selection of port removable bits, port used bits, and USB2_ONLY bits.
0 = rmbl[3:0], used[3:0], and USB2_ONLY[3:0] are read only and the values are loaded from the OTP ROM
1 = rmbl[3:0], used[3:0], and USB2_ONLY[3:0] are read/write and can be loaded by EEPROM or written by SMBus
This bit can be written simultaneously with rmbl[3:0].
6:4RSVDROReserved. Read only, returns 0 when read.
3:0rmbl[3:0]RO/RWRemovable. The bits in this field indicate whether a device attached to downstream ports 4 through 1 are removable or permanently attached.
0 = The device attached to the port is not removable
1 = The device attached to the port is removable
Each bit corresponds directly to a downstream port n + 1, that is rmbl0 corresponds to downstream port 1, rmbl1 corresponds to downstream port 2, and so forth.
This field is read only unless the customRmbl bit is set to 1. Otherwise the value of this filed reflects the inverted values of the OTP ROM non_rmb[3:0] field.