2.7 Transmit De-Emphasis
Enter any value between 0.0 and 36.1 (in dB) in the Required edit box for both Pre-Transmit and Post-Transmit stage. Not all values are supported. See the following table for all actual values supported.
The value you enter in the Required box is matched to the closest valid actual value and reported in the actual box.
The Configurator sets appropriate values for LANE<n>_TX_PRE_RATIO and LANE<n>_TX_PST_RATIO registers based on the Actual value, as shown in the following table.
The default value for Required is 0 for Pre-Transmit and 3.5 for Post-Transmit.
The LANE<n>_TX_AMP_RATIO lane register is always set to 0x80 for all lanes.
| Feature | Control Registers | Actual Value = Value Programmed in Register |
|---|---|---|
De-Emphasis Pre | LANE<n>_TX_PRE_RATIO | 0 dB = 0x0 0.1 dB = 0x1 0.3 dB = 0x2 |
De-Emphasis Post | LANE<n>_TX_PST_RATIO | 0.4 dB = 0x3 0.5 dB = 0x4 0.7 dB = 0x5 0.9 dB = 0x6 1 dB = 0x7 1.2 dB = 0x8 1.3 dB = 0x9 1.5 dB = 0xa 1.6 dB = 0xb 1.8 dB = 0xc 2 dB = 0xd 2.1 dB = 0xe 2.3 dB = 0xf 2.5 dB = 0x10 2.7 dB = 0x11 2.9 dB = 0x12 3 dB = 0x13 3.3 dB = 0x14 3.5 dB = 0x15 3.7 dB = 0x16 3.9 dB = 0x17 4 dB = 0x18 4.3 dB = 0x19 4.5 dB = 0x1a 4.8 dB = 0x1b |
De-Emphasis Post (contd.) | LANE<n>_TX_PST_RATIO (contd.) | 5 dB = 0x1c 5.2 dB = 0x1d 5.5 dB = 0x1e 5.8 dB = 0x1f 6 dB = 0x20 6.3 dB = 0x21 6.5 dB = 0x22 7 dB = 0x23 7.2 dB = 0x24 7.5 dB = 0x25 7.8 dB = 0x26 8 dB = 0x27 8.5 dB = 0x28 9 dB = 0x29 9.3 dB = 0x2a 9.7 dB = 0x2b |
De-Emphasis Post (contd.) | LANE<n>_TX_PST_RATIO (contd.) | 10.1 dB = 0x2c 10.5 dB = 0x2d 11 dB = 0x2e 11.5 dB = 0x2f 12 dB = 0x30 12.6 dB = 0x31 13.2 dB = 0x32 13.8 dB = 0x33 14.5 dB = 0x34 15.2 dB = 0x35 16.1 dB = 0x36 17 dB = 0x37 18 dB = 0x38 19.2 dB = 0x39 20.5 dB = 0x3a 22.1 dB = 0x3b 24 dB = 0x3c 26.5 dB = 0x3d 30.1 dB = 0x3e 36.1 dB = 0x3f |
- LANE<n>_TX_PRE_RATIO registers are set to 0x10
- LANE<n>_TX_PST_RATIO registers are set to 0x10
- LANE<n>_TX_AMP_RATIO registers are set to 0x80