13–2
Chapter 13: Error Handling
Physical Layer Errors
Arria V GZ Hard IP for PCI Express
November 2012
Altera Corporation
Physical Layer Errors
describes errors detected by the Physical Layer.
P
Data Link Layer Errors
describes errors detected by the Data Link Layer.
Table 13–2. Errors Detected by the Physical Layer
Error
Type
Description
Receive port error
Correctable
This error has the following 3 potential causes:
■
Physical coding sublayer error when a lane is in L0 state. These errors
are reported to the Hard IP block via the per lane PIPE interface input
receive status signals,
rxstatus<lane_number>[2:0]
using the
following encodings:
100: 8B/10B Decode Error
101: Elastic Buffer Overflow
110: Elastic Buffer Underflow
111: Disparity Error
■
Deskew error caused by overflow of the multilane deskew FIFO.
■
Control symbol received in wrong lane.
Note to
:
(1) Considered optional by the PCI Express specification.
Table 13–3. Errors Detected by the Data Link Layer
Error
Type
Description
Bad TLP
Correctable
This error occurs when a LCRC verification fails or when a sequence
number error occurs.
Bad DLLP
Correctable
This error occurs when a CRC verification fails.
Replay timer
Correctable
This error occurs when the replay timer times out.
Replay num rollover
Correctable
This error occurs when the replay number rolls over.
Data Link Layer protocol
Uncorrectable
(fatal)
This error occurs when a sequence number specified by the Ack/Nak
block in the Data Link Layer (
AckNak_Seq_Num)
does not correspond to
an unacknowledged TLP. (Refer to