3. RapidIO Lanes > Port and Lane Initialization Sequence
CPS-1848 User Manual
80
June 2, 2014
Formal Status
This document is confidential and is subject to an NDA.
Integrated Device Technology
As the TX_AMP_CTL value in the
is increased, the waveform amplitude increases. The following
graph shows the change in the amplitude as the register (DAC) value is increased. The amplitude is measured in volts
peak-to-peak differential.
3.4.1.2
Receiver DFE Control
The receiver DFE function is controlled by fields in the
. DFE is
enabled using the
.RX_DFE_DIS bit.
The CPS-1848 receiver DFE design has five “taps” numbered 0 to 4, in addition to a tap offset value. These values can be
controlled through register accesses. The programming model for software control of the receiver DFE taps makes use of a
paired “select” control bit and a tap value field for each tap. The following are the pairs of select control bits and tap values:
•
.TAP_0_SEL and
.TAP_0_CFG
•
.TAP_1_SEL and
.TAP_1_CFG
•
.TAP_2_SEL and
.TAP_2_CFG
•
.TAP_3_SEL and
.TAP_3_CFG
•
.TAP_4_SEL and
.TAP_4_CFG
The “select” control bit must be set to 1 in order for the associated tap value field to have any effect. IDT recommends that Tap
4 should be half the value of Tap 3, Tap 3 should be half the value of Tap 2, and Tap 2 should be half the value of Tap 1. Note
that the signed Tap values should all be positive.
To load tap values, the
.CFG_EN bit must transition from 0 to 1.