User guide

16–18 Chapter 16: Transceiver Reconfiguration Controller IP Core
Controlling DFE Using Register-Based Reconfiguration
Altera Transceiver PHY IP Core November 2012 Altera Corporation
User Guide
Controlling DFE Using Register-Based Reconfiguration
In register-based mode, you use a sequence of Avalon-MM writes and reads to
configure DFE and turn DFE on and off.
Complete the following steps to turn on DFE Adaptive mode:
1. Read the DFE control and status register
busy bit (bit 8) until it is clear.
2. Write the logical channel number of the channel to be updated to the DFE logical
channel number register.
3. Write the
DFE_offset address to 0x0.
4. Write the data value 2'b11 to the data register. This data powers on DFE and
enables the DFE adaptation engine.
5. Write the
control and status register write bit to 1'b1.
6. Read the
control and status register busy bit. Continue to read the busy bit while
its value is 1b’1.
7. When busy = 1’b0, the Transceiver Reconfiguration Controller has updated the
logical channel specified in Step 2 with the data specified in Steps 3 and 4.
0x3
[3] RW
tap 3 polarity
Specifies the polarity of the third post tap as follows:
■ 0: negative polarity
■ 1: positive polarity
[2:0] RW
tap 3
Specifies the coefficient for the third post tap. The valid
range is 0–7.
0x4
[3] RW
tap 4 polarity
Specifies the polarity of the fourth post tap as follows:
■ 0: negative polarity
■ 1: positive polarity
[2:0] RW
tap 4
Specifies the coefficient for the fourth post tap. The valid
range is 0–7.
0x5
[3] RW
tap 5 polarity
Specifies the polarity of the fifth post tap as follows:
■ 0: negative polarity
■ 1: positive polarity
[2:0] RW
tap 5
Specifies the coefficient for the fifth post tap. The valid
range is 0–3.
0xa [0] WO
DFE_calibration
Writing a 1 to this bit initiates DFE manual calibration on
the specified channel.
0xb [0] WO
DFE_adaptation
Writing a 1 to this bit initiates DFE 1-time adaptation on
the specified channel.
Table 16–15. DFE Offset and Values (Part 2 of 2)
Offset Bits R/W Register Name Description