The Gen3/Gen4 TX and RX equalization defined here is different from the PIPE specification. The custom Gen3/Gen4 equalization scheme described here must be used for any third-party PCIe controllers. For more details, refer to Equalization Sequences.
Name | Width | I/O | Clock Domain | Description | |||||||||||||||||||||||||||||||||||||||
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phy_txeq_ctrl[1:0] | 2 | Input | pclk | TX equalization control. Must set back to 00b when txeq_done = 1b is
detected.
Gen3 and
Gen4 speeds only. Per-lane.
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phy_txeq_preset[3:0] | 4 | Input | pclk | Set the TX equalization to one of the defined preset when txeq_ctrl =
01b. Must use txeq_ctrl to change the preset, otherwise the default
preset 0100b is used.
Gen3 and Gen4 speeds
only. Per-lane.
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phy_txeq_coeff[5:0] | 6 | Input | pclk | Set the TX equalization to a custom coefficient when txeq_control =
10b. Three consecutive pclk cycles are required to register the new
18-bit TX coefficient.
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phy_txeq_fs[5:0] | 6 | Output | pclk | Indicates the full swing of the TX driver. Static value based on characteristics of TX driver. .Gen3 and Gen4 speeds only. | |||||||||||||||||||||||||||||||||||||||
phy_txeq_lf[5:0] | 6 | Output | pclk | Indicates the low frequency of the TX driver. Static value based on characteristics of TX driver. Gen3 and Gen4 speeds only. | |||||||||||||||||||||||||||||||||||||||
phy_txeq_new_coeff[17:0] | 18 | Output | pclk | Shows the status of the current TX equalization coefficient.
Gen3 and Gen4 speeds
only. Per-lane.
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phy_txeq_done | 1 | Output | pclk | This port is High when TXEQ is equalization done. Single cycle done
indicator for txeq_control .
Gen3 and Gen4 speeds only.
Per-lane.
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dbg_phy_txeq_fsm | 3 | Output | pclk | Tell TX EQ FSM
state: FSM_IDLE = 3’d0 FSM_PRESET = 3’d1 FSM_COEFF = 3’d2 FSM_REMAP = 3’d3 FSM_QUERY = 3’d4 FSM_DONE = 3’d5 |