px1011a NXP Semiconductors, px1011a Datasheet - Page 16

• Manufacturer Part Number: px1011a
• Description: Px1011a/px1012a Pci Express Stand-alone X1 Phy
• Manufacturer: NXP Semiconductors

Philips Semiconductors
PX1011A_PX1012A_2
Product data sheet
8.10.1 8b/10b decode errors
8.10.2 Disparity errors
8.10.3 Elastic buffer
For a detected 8b/10b decode error, the PHY places an EDB (EnD Bad) symbol in the
data stream in place of the bad byte, and encodes RXSTATUS with a decode error during
the clock cycle when the effected byte is transferred across the parallel interface. In
Figure 11
an 8b/10b decode error. In place of that byte, the PHY places an EDB on the parallel
interface, and sets RXSTATUS to the 8b/10b decode error code. Note that a byte that
cannot be decoded may also have bad disparity, but the 8b/10b error has precedence.
For a detected disparity error, the PHY asserts RXSTATUS with the disparity error code
during the clock cycle when the effected byte is transferred across the parallel interface. In
Figure 12
the assertion of RXSTATUS.
For elastic buffer errors, an underflow is signaled during the clock cycle when the spurious
symbol is moved across the parallel interface. The symbol moved across the interface is
the EDB symbol. In the timing diagram
symbols Rx-a through Rx-z. The elastic buffer underflow causing the EDB symbol to be
inserted between the Rx-c and Rx-d symbols. The PHY drives RXSTATUS to indicate
buffer underflow during the clock cycle when the EDB is presented on the parallel
interface.
Fig 11. 8b/10b decode errors
Fig 12. Disparity errors
RXDATA[7:0]
RXSTATUS2,
RXSTATUS1,
RXSTATUS0
RXDATA[7:0]
RXSTATUS2,
RXSTATUS1,
RXSTATUS0
RXVALID
RXVALID
the receiver is receiving a stream of bytes Rx-a through Rx-z, and byte Rx-c has
the receiver detected a disparity error on Rx-c data byte, and indicates this with
RXCLK
RXCLK
Rx-a
000b
Rx-a
000b
Rev. 02 — 18 May 2006
Rx-b
Rx-b
Figure
100b
111b
EDB
Rx-c
13, the PHY is receiving a repeating set of
PX1011A/PX1012A
PCI Express stand-alone X1 PHY
Rx-d
000b
Rx-d
000b
© Koninklijke Philips Electronics N.V. 2006. All rights reserved.
Rx-e
Rx-e
001aac780
001aac781
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