Do you have a tuning guide for the DS160PT801? The required speeds are Gen1, Gen2, and Gen3. The link width is x8.
We must disable equalization on the upstream side and use fixed TX preset, CTLE, and gain settings. Ideally, equalization should be enabled on the downstream side, but fixed settings will work. Can you provide guidance on configuring the DS160PT801 with the following settings?
- Disable equalization on the upstream side.
- TX preset – 4
- Minimum or no CTLE – what the CTLE index in the channel registers means.
- Minimum gain – what the RX VGA index in the channel registers means.
- Enable or disable equalization on the downstream side. If equalization is disabled, we will use fixed settings similar to the upstream side.
We use initialization values described in the datasheet and provided in the EEPROM images. In addition, we set 0x9D=0x44 (requested Gen3 TX preset value for retimer) and 0xB6=0x08 (Disable DFE) in the channel registers. The link works, but the retimer initiates equalization, although the equalization is disabled in the upstream and downstream components. As a result, the link does not tune to the optimal values and results in RX and DLL errors on the PCIe link.