SNAU305 February   2025 LMH1229 , LMH1239

 

  1.   1
  2.   LMH1229 and LMH1239 Programming Guide
  3.   Trademarks
  4. 1Access Methods
    1. 1.1 Register Programming Through SMBus
    2. 1.2 Register Programming Through SPI
    3. 1.3 Register Pages
  5. 2Register Command Syntax
  6. 3Device Configurations
    1. 3.1  Common Device Configuration
    2. 3.2  Common Register Commands
      1. 3.2.1 Channel Control
      2. 3.2.2 LMH12x9 Resets
        1. 3.2.2.1 LMH12x9 ENABLE Pin Override
        2. 3.2.2.2 LMH12x9 Share, CDR, and EQ/Drivers Page Resets
    3. 3.3  IN_MUX_SEL Override
    4. 3.4  Signal Detect Status for SDI_IN± and SDI_IN1±
      1. 3.4.1 Force Signal Detect Power Down
    5. 3.5  Lock Data Rate Indication
    6. 3.6  CDR Loop Bandwidth Override
    7. 3.7  Selective SMPTE Data Rate Lock
      1. 3.7.1 Digital Mute Reference Threshold
      2. 3.7.2 CTLE Index Check and Manual CTLE Override
    8. 3.8  Eye Opening Monitoring Operation
      1. 3.8.1 Fast EOM
        1. 3.8.1.1 Fast EOM Operation
      2. 3.8.2 Read Horizontal and Vertical Eye Opening
    9. 3.9  SDI_OUT±, OUT0± and OUT1± Default Mode of Operation
      1. 3.9.1 SDI_OUT±, OUT0± and OUT1± Independent Control
    10. 3.10 Invert OUT0±, OUT1±, and SDI_OUT± Data Polarity
    11. 3.11 OUT0±, OUT1±, and SDI_OUT± Driver Settings
      1. 3.11.1 OUT0± and OUT1± VOD Settings
      2. 3.11.2 OUT0± and OUT1± De-Emphasis Settings
      3. 3.11.3 SDI_OUT± VOD Settings
      4. 3.11.4 SDI_OUT± Pre-Emphasis
      5. 3.11.5 Output Driver Power Down
      6. 3.11.6 Cable Fault Detection (CFD)
    12. 3.12 LOCK_N Pin Output Settings
      1. 3.12.1 Interrupt Outputs Programmed by Interrupt Registers
    13. 3.13 PRBS Generator and Checker
    14. 3.14 CDR Lock Timing Control
      1. 3.14.1 Watchdog Timer
  7. 4Register Maps
    1. 4.1 Share Registers
    2. 4.2 CDR Registers
    3. 4.3 EQ_Drivers Registers

3.2.2.1 LMH12x9 ENABLE Pin Override

Using share page 0xFA, the user can override the ENABLE pin to restart the LMH12x9 state machine. The ENABLE pin can be used to force the LMH12x9 into power down. While the ENABLE pin is low, register access remains active. Disabling and re-enabling the device restarts the cable equalizer adaptation process and CDR lock.

Table 3-5 LMH12x9 ENABLE Pin Override
COMMANDREGISTERVALUEMASK//COMMENTS
RAWFF0007//Enable Share Register Page
RAWFA80

80

//Override the ENABLE pin

RAWFA00

40

//Disable the device

RAW

FA

40

40

//Enable the device

RAW

FA

00

80

//Disable the ENABLE pin override