User guide

8–4 Chapter 8: Low Latency PHY IP Core
Parameter Settings
Altera Transceiver PHY IP Core User Guide December 2010 Altera Corporation
Table 8–4 describes the Analog Options tab. Many of the analog options control
pre-emphasis. Programmable pre-emphasis boosts high frequencies in the transmit
data signal, which might be attenuated in the transmission media. Using
pre-emphasis can maximize the data opening at the far-end receiver. By applying
pre-emphasis, the high-frequency components are boosted; that is, pre-emphasized.
There are three pre-emphasis taps—pre-tap, first post-tap, and second post-tap. The
pre-tap sets the pre-emphasis on the data bit before the transition. The first post-tap
and second post-tap set the pre-emphasis on the transition bit and the successive bit,
respectively. The pre-tap and second post-tap also provide inversion control. These
settings are only required for Stratix IV GX and GT. These are automatically calculated
for Stratix V GX devices.
Parameters for Stratix IV and Derivatives
PLL type CMU, ATX
Allows you to choose a clock multiplier unit (CMU) or auxiliary
transmit (ATX) PLL. The CMU PLL is designed to achieve low TX
channel-to-channel skew. The ATX PLL is designed to improve
jitter performance. This option is only available for Stratix IV GX
devices.
Starting channel number 0–96 The physical channel number for this transceiver channel.
Note to Table 8–3:
(1) For more information refer to the “FPGA Fabric-Transceiver Interface Clocking” section in the Stratix IV Transceiver Clocking chapter.
Table 8–3. Additional Options (Part 2 of 2)
Name Value Description
Table 8–4. PMA Analog Options (Part 1 of 2)
Name Value Description
TX termination resistance
OCT_85_OHMS
OCT_100_OHMS
OCT_120_OHMS
OCT_150_OHMS
Indicates the value of the termination resistor for the transmitter.
Select the transmitter VOD
control setting
0–7 Sets V
OD
for the various TX buffers.
Pre-emphasis pre-tap setting 0–7 Sets the amount of pre-emphasis on the TX buffer.
Enable the pre-emphasis pre-tap
polarity inversion
On
Off
Determines whether or not the pre-emphasis control signal for the
pre-tap is inverted. If you turn this option on, the pre-emphasis
control signal is inverted.
Select the TX pre-emphasis first
post-tap setting
0–15 Sets the amount of pre-emphasis for the 1st post-tap.
Specifies the pre-emphasis
second post-tap setting
0–7 Sets the amount of pre-emphasis for the 2nd post-tap.
Enable the pre-emphasis second
post-tap polarity inveresion
On
Off
Determines whether or not the pre-emphasis control signal for the
second post-tap is inverted. If you turn this option on, the
pre-emphasis control signa is inverted.
Select the receiver common
mode voltage
TRISTATE
0.82V
1.1v
Specifes
the RX common mode voltage.