Altera Transceiver PHY IP Core User Manual
Page 197
Signal Name
Direction
Description
pipe_g3_txdeemph[17:0]
Input
For Gen3, selects the transmitter de-emphasis. The
18 bits specify the following coefficients:
• [5:0]: C
-1
• [11:6]: C
0
• [17:12]: C
+1
for presets to TX de-emphasis
mappings.
In Gen3 capable designs, the TX deemphasis for
Gen2 data rates is always -6 dB. The TX
deemphasis for Gen1 data rate is always -3.5 dB.
pipe_txmargin[3<n>-1:0]
Input
Transmit V
OD
margin selection. The MAC PHY
sets the value for this signal based on the value
from the Link Control 2 Register. The following
encodings are defined:
• 3'b000: Normal operating range
• 3'b001: Full swing: 800 - 1200 mV; Half swing:
400 - 700 mV
• 3'b010:–3’b011: Reserved
• 3'b100–3’b111: If last value, full swing: 200 - 400
mV, half swing: 100 - 200 mV else reserved
pipe_txswing
Input
Indicates whether the transceiver is using full- or
low-swing voltages as defined by the
tx_
pipemargin
.
• 1’b0–Full swing.
• 1’b1–Low swing.
pipe_rxpolarity
Input
When 1, instructs the PHY layer to invert the
polarity on the received data.
pipe_rate[1:0]
Input
The 2-bit encodings have the following meanings:
• 2’b00: Gen1 rate (2.5 Gbps)
• 2’b01: Gen2 rate (5.0 Gbps)
• 2’b1x: Gen3 (8.0 Gbps)
The Rate Switch from Gen1 to Gen2 Timing
Diagram illustrates the timing of a rate switch from
Gen1 to Gen2 and back to Gen1.
UG-01080
2015.01.19
PHY for PCIe (PIPE) Input Data from the PHY MAC
8-9
PHY IP Core for PCI Express (PIPE)
Altera Corporation