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 |