Sata Oob Detection - Xilinx Virtex-5 RocketIO GTP User Manual

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SATA OOB Detection

Each GTP transceiver includes a SATA OOB detector to decode SATA COM sequences.
When RX_STATUS_FMT is set to SATA, the pins of the RXSTATUS port are used to indicate
the arrival of COM sequences.
down to create a squelch clock that runs at approximately 25 MHz. This clock is used to
sample the output of the block that detects OOB signals to look for transitions between
regular data and OOB signals. Both edges of the squelch clock are used. The squelch
detector FSM uses the transitions to calculate the length of each burst and each idle. It uses
this information to drive the RXSTATUS port, indicating which COM sequences have been
found.
OOB_CLK_DIVIDER
Before the SATA OOB detector can work, it must be configured to use the reference clock
provided (CLKIN). The OOB_CLK_DIVIDER attribute must be set to produce a squelch
clock between 25 MHz and 37.5 MHz, and as close to 25 MHz as possible. In addition, the
MIN and MAX times for bursts and idles must be set based on the squelch clock rate. The
formula to set the squelch clock is shown below:
All the minimum values are defined with a minimum time below which the signal must be
rejected, and a minimum time above which the signal always meets the minimum time
requirement. After calculating each of these in terms of squelch clock cycles, the
appropriate MIN parameter is set to an integer value between these two numbers.
Similarly, for all maximum values, there is a maximum time above which the signal must
be rejected, and a maximum time below which the signal always meets the maximum time
requirement. After calculating these in terms of squelch clock, the appropriate MAX
parameter is set to an integer value between these two numbers.
Virtex-5 RocketIO GTP Transceiver User Guide
UG196 (v1.3) May 25, 2007
RXP
RXN
OOBDETECT_THRESHOLD
CLKIN
Squelch
Divider
Figure 7-3: SATA OOB Detector Block Diagram
⎛
Parameter in squelch cycles =
⎝
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Figure 7-3 shows the SATA OOB detector. It divides CLKIN
Peak
amp
Detector
D Q
D Q
Squelch
Clock
SATA_MIN_BURST
SATA_MAX_BURST
SATA_MIN_INIT
SATA_MAX_INIT
SATA_MIN_WAKE
SATA_MAX_WAKE
Parameter in ns ⎞
×
---------------------------------------- -
squelch clock frequency in MHz
⎠
1000
RX OOB/Beacon Signaling
RXELECIDLE
COMINIT
Squelch
FSM
COMWAKE
UG196_c7_03_013007
×
Equation 7-1
2
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