SNLU288 December 2020
Each DS160PR412 and DS160PR421 deploys an RX Detect state machine that governs the RX detection cycle as defined in the PCI Express specification. At power up or after a manually triggered event, the redriver determines whether or not a valid PCI Express termination is present at the far end of the link. The RX_DET/SCL pin of DS160PR412 and DS160PR421 provides additional flexibility to system designers to appropriately set the device in their desired mode, according to Table 2-5.
| PD PIN LEVEL | RX_DET/SCL PIN LEVEL | DESCRIPTION |
|---|---|---|
| L | L0 | PCI Express RX detection state machine is disabled. Recommended for non-PCI Express use cases. Inputs are always 50 Ω. |
| L | L1 | PCI Express RX detection state machine is enabled. Recommended for PCI Express use cases. Pre Detect: Hi-Z, Post Detect: 50 Ω. Outputs poll every approximately 150 μs until three consecutive valid RX termination detections. |
| L | L2 | PCI Express RX detection state machine is enabled. Recommended for PCI Express use cases. Pre Detect: Hi-Z, Post Detect: 50 Ω. Outputs poll every approximately 150 μs until two consecutive valid RX termination detections. |
| L | L3 (Float) | PCI Express RX detection state machine is enabled. Recommended for PCI Express use cases. Pre Detect: Hi-Z, Post Detect: 50 Ω. Outputs poll every approximately 150 μs until a valid RX termination detection. |
| H | X | Manual reset, inputs are Hi-Z |