Digital Monitor
The receiver uses an adaptive algorithm in optimizing a link. The digital monitor provides visibility
into the current state of these adaptation loops. Digital monitor requires a clock such as
DRPCLK. CH0/1_RXUSRCLK2 can be used for this. The attributes
CH0/1_RX_APT_CFG14A[15:12] and CH0/1_RX_APT_CFG18B[15:12] select the adaptation
loops monitored on the CH0_DMONITOROUT and CH1_DMONITOROUT ports. The output
ports CH0_DMONITOROUT and CH1_DMONITOROUT contain the current code(s) for a
selected loop. A loop has three steady states: min, max, or dithering.
Ports and Attributes
The following table shows the GTM digital monitor ports.
Table 26: Digital Monitor Ports
Port
Dir
Clock Domain
Description
CH[0/1]_DMONITOROUT[31:0]
Out
Async/Local Clock
Digital monitor output bus for channel
0/1.
CH[0/1]_DMONITORCLK
In
Async
Channel 0/1 digital monitor clock.
CH[0/1]_DMONITORFIFORESET
In
Async
Reserved. Tie to GND.
CH[0/1]_DMONITOROUTCLK
Out
Async
Channel 0/1 internal clock from
adaptation loops.
DMONITOROUTPLLCLK
Out
Async
Internal TX calibration clock.
The following table shows the GTM digital monitor attributes.
Table 27: Digital Monitor Attributes
Attribute
Type
Description
CH[0/1]_RX_MON_CFG
16-bit
Reserved.
Bit Name
Bit Field
Description
DMON_ENABLE
[0]
Enables digital monitor for channel 0/1.
DMON_SRC
[2:1]
Enables RX DMON path for channel 0/1. Must be set to
2’b00
when
reading RX adaptation loops.
Chapter 2: Shared Features
UG581 (v1.0) January 4, 2019
Virtex Ult GTM Transceivers
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