XRS10L240 Datasheet, PDF (10/38 Pages) Exar Corporation – SERIAL ATA II: PORT MULTIPLIER / PORT SELECTOR

EXSTOR - 1 XRS10L240
SERIAL ATA II: PORT MULTIPLIER / PORT SELECTOR
REV. 1.05
3.1 Out Of Band Feature
Each Serial ATA link provides full support for the three Out Of Band (OOB) signals supported by Serial ATA:
COMRESET, COMINIT and COMWAKE. These sequences must be separated by idle periods as shown in
Figure 5. The sequences are comprised of 106.7ns bursts of activity that are interleaved with varying length
stretches of electrical idle. This alternating sequence must be repeated four times to be recognized.
FIGURE 5. COMWAKE AND COMRESET/COMINIT SEQUENCES
106.7ns
COMWAKE
106.7ns
COMRESET
COMINIT
320ns
An example OOB sequence and the resulting burst and idle widths are shown in Figure 6. If the sequence of
burstWidth and idleWidth counts falls within the range specified in the MDIO registers for four consecutive
burst/idle sequences, then the link will assert COMINIT or COMWAKE. This OOB signal will remain asserted
for as long as the corresponding sequence on the input pins continues.
FIGURE 6. EXAMPLE OOB SEQUENCE
rxdP, rxdN
squelchClock
burstWidth
15
15
15
idleWidth
17
17
17
COMINT = (MaxBurstWidth≥burstWidth≥MinBurstWidth) && (MaxInitWidth≥idleWidth≥MinInitWidth)
COMWAKE = (MaxBurstWidth≥burstWidth≥MinBurstWidth) && (MaxWakeWidth≥idleWidth³MinWakeWidth)
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