SNLS398H January   2012  – February 2018 DS125DF410

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Typical Application Diagram
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 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 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Device Data Path Operation
      2. 7.3.2 Signal Detect
      3. 7.3.3 CTLE
      4. 7.3.4 DFE
      5. 7.3.5 Clock and Data Recovery
      6. 7.3.6 Output Driver
      7. 7.3.7 Device Configuration
        1. 7.3.7.1 Rate and Subrate Setting
    4. 7.4 Device Functional Modes
      1. 7.4.1 SMBus Master Mode and SMBus Slave Mode
      2. 7.4.2 Address Lines <ADDR_[3:0]>
      3. 7.4.3 SDA and SDC
      4. 7.4.4 Standards-Based Modes
        1. 7.4.4.1 Ref_mode 3 Mode (Reference Clock Required)
        2. 7.4.4.2 False Lock Detector Setting
        3. 7.4.4.3 Reference Clock In
        4. 7.4.4.4 Reference Clock Out
        5. 7.4.4.5 Driver Output Voltage
        6. 7.4.4.6 Driver Output De-Emphasis
        7. 7.4.4.7 Driver Output Rise/Fall Time
        8. 7.4.4.8 INT
        9. 7.4.4.9 LOCK_3, LOCK_2, LOCK_1, and LOCK_0
    5. 7.5 Programming
      1. 7.5.1  SMBus Strap Observation
      2. 7.5.2  Device Revision and Device ID
      3. 7.5.3  Control/Shared Register Reset
      4. 7.5.4  Interrupt Channel Flag Bits
      5. 7.5.5  SMBus Master Mode Control Bits
      6. 7.5.6  Resetting Individual Channels of the Retimer
      7. 7.5.7  Interrupt Status
      8. 7.5.8  Overriding the CTLE Boost Setting
      9. 7.5.9  Overriding the VCO Search Values
      10. 7.5.10 Overriding the Output Multiplexer
      11. 7.5.11 Overriding the VCO Divider Selection
      12. 7.5.12 Using the PRBS Generator
      13. 7.5.13 Using the Internal Eye Opening Monitor
      14. 7.5.14 Overriding the DFE Tap Weights and Polarities
      15. 7.5.15 Enabling Slow Rise/Fall Time on the Output Driver
      16. 7.5.16 Inverting the Output Polarity
      17. 7.5.17 Overriding the Figure of Merit for Adaptation
      18. 7.5.18 Setting the Rate and Subrate for Lock Acquisition
      19. 7.5.19 Setting the Adaptation/Lock Mode
      20. 7.5.20 Initiating Adaptation
      21. 7.5.21 Setting the Reference Enable Mode
      22. 7.5.22 Overriding the CTLE Settings Used for CTLE Adaptation
      23. 7.5.23 Setting the Output Differential Voltage
      24. 7.5.24 Setting the Output De-Emphasis Setting
    6. 7.6 Register Maps
      1. 7.6.1 Register Information
      2. 7.6.2 Bit Fields in the Register Set
      3. 7.6.3 Writing to and Reading from the Control/Shared Registers
      4. 7.6.4 Channel Select Register
      5. 7.6.5 Reading to and Writing from the Channel Registers
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Trademarks
    3. 11.3 Electrostatic Discharge Caution
    4. 11.4 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

7.6.3 Writing to and Reading from the Control/Shared Registers

Any write operation targeting register 0xff writes to the control/shared register 0xff. This is the only register in the DS125DF410 with an address of 0xff.

Bit 2 of register 0xff is used to select either the control/shared register set or a channel register set. If bit 2 of register 0xff is cleared (written with a 0), then all subsequent read and write operations over the SMBus are directed to the control/shared register set. This situation persists until bit 2 of register 0xff is set (written with a 1).

There is a register with address 0x00 in the control/shared register set, and there is also a register with address 0x00 in each channel register set. If you read the value in register 0x00 when bit 2 of register 0xff is cleared to 0, then the value returned by the DS125DF410 is the value in register 0x00 of the control/shared register set. If you read the value in register 0x00 when bit 2 of register 0xff is set to 1, then the value returned by the DS125DF410 is the value in register 0x00 of the selected channel register set. The channel register set is selected by bits 1:0 of register 0xff.

If bit 3 of register 0xff is set to 1 and bit 2 of register 0xff is also set to 1, then any write operation to any register address will write all the channel register sets in the DS125DF410 simultaneously. This situation will persist until either bit 3 of register 0xff or bit 2 of register 0xff is cleared. Note that when you write to register 0xff, independent of the current settings in register 0xff, the write operation ALWAYS targets the control/shared register 0xff. This channel select register, register 0xff, is unique in this regard.

Table 14 below shows the control/shared register set. Any register addresses or register bits in the control/shared register set not shown in this table should be considered reserved. In this table, the mode is either R for Read-Only, R/W for Read-Write, or R/W/SC for Read-Write-Self-Clearing. If you try to write to a Read-Only register, the DS125DF410 will ignore it.

Table 14. Control/Shared Registers

Address (Hex)BitsDefault Value (Hex)ModeEEPROMField NameDescription
0 7 0 R N SMBus_Addr3 SMBus Address
6 0 R N SMBus_Addr2 Strapped 7-bit address is 0x18 + SMBus_Addr[3:0]
5 0 R N SMBus_Addr1
4 0 R N SMBus_Addr0
3:0 0 RESERVED
1 7 1 R N Version2 Device version
6 1 R N Version1
5 0 R N Version0
4 1 R N Device_ID4 Device ID code
3 0 R N Device_ID3
2 0 R N Device_ID2
1 0 R N Device_ID1
0 1 R N Device_ID0
2 7:0 0 RW N RESERVED
3 7:0 0 N RESERVED
4 7 0 RW N RESERVED
6 0 RWSC N RST_SMB_REGS 1: Resets share registers. Self-clearing.
5 0 RWSC N RST_SMB_MAS 1: Reset for SMBus Master Mode
4 0 RW N rc_eeprm_rd 1: Force EEPROM Configuration
3 0 RW N RESERVED
2 0 RW N RESERVED
1 0 RW N RESERVED
0 1 RW N RESERVED
5 7 0 RW N disab_eeprm_cfg Disable Master Mode EEPROM Configuration
6:5 0 RW N RESERVED
4 1 R N EEPROM_READ_DONE This bit is set to 1 when read from EEPROM is done
3 0 R N int_ch0 Set on Channel 0 Interrupt
2 0 R N int_ch1 Set on Channel 1 Interrupt
1 0 R N int_ch2 Set on Channel 2 Interrupt
0 0 R N int_ch3 Set on Channel 3 Interrupt
6 7:0 0 RW N RESERVED
7 7:0 0x05 RW N RESERVED
FF 7:4 0 RW N RESERVED
3 0 RW N WRITE_ALL_CH Selects All Channels for Register Write. See Table 15.
2 0 RW N EN_CH_SMB Enable Register Write to One or all Channels and Register Read from One Channel. See Table 15.
1:0 0 RW N SEL_CH_SMB Selects Target Channel for Register Reads and Writes. See Table 15.