SNLA299 August   2018 LMH0324 , LMH0397 , LMH1208 , LMH1218 , LMH1219 , LMH1297

 

  1.   LMH12xx MADI Compatibility Application Note
    1.     Trademarks
    2. 1 MADI Specification Requirements
      1. 1.1 MADI Transmitter Electrical Requirements
        1. 1.1.1 Line Driver Impedance
        2. 1.1.2 Mean Output Voltage
        3. 1.1.3 Maximum Output Voltage
        4. 1.1.4 Terminated Signal Rise and Fall Time
      2. 1.2 MADI Receiver Electrical Requirements
    3. 2 LMH12xx Device Family
      1. 2.1 LMH12xx Device Family
        1. 2.1.1 LMH1297 MADI Modes of Operation
          1. 2.1.1.1 Dual MADI Cable Driver
          2. 2.1.1.2 SDI Bidirectional IO and MADI Cable Driver
          3. 2.1.1.3 Bidirectional MADI Port and SDI MADI Cable Driver
          4. 2.1.1.4 Bidrectional MADI Port and SDI Cable Driver
        2. 2.1.2 LMH1297 Device Family Register Changes for MADI Compatibility
        3. 2.1.3 LMH1297 Device Family Hardware Changes for MADI Compatibility
      2. 2.2 LMH1218 Device Family Hardware Changes to Support MADI Compatibility
      3. 2.3 LMH1219 Device Family Recommended Register Settings
    4. 3 Summary
    5. 4 References

2.1.2 LMH1297 Device Family Register Changes for MADI Compatibility

After a 75-Ω termination, output voltage should be within 0.3 V to 0.6 V. In default mode, LMH1297 device family supports SDI amplitude dynamic range. To support MADI output voltage range through SMBus or SPI interface, the following register settings are necessary:

RAW FF 05 07 //enable config_io register set

RAW 61 80 80 //sdi_io vod ov enable

RAW 61 32 7F //sdi_io vod equal to 0x32

RAW 68 80 80 //sdi_out vod override enable

RAW 68 32 7F //sdi_out vod equal to 0x32

RAW 60 20 20 //force sdi_io slew rate

RAW 60 00 18 //select sd slew rate for sdi_io

RAW 68 20 20 //force sdi_out slew rate

RAW 68 00 18 //select sd slew rate for sdi_out

RAW FF 04 07 //retimer register set enable

RAW 3F 08 08 //override out_ctrl pin

RAW 09 00 20 //disable independent control

RAW 1C 0C 0C //raw sdi_out and out0