Effect of link management packet corruption, Error events & handling, Error events & handling –69 – Altera SerialLite II Protocol User Manual
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Altera Corporation
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SerialLite II Protocol Reference Manual
SerialLite II Specification
Figure 2–42. Retry-On-Error Example
Notes to
(1)
Device A transmits Seg_A, Seg_B, and Seg_C to Port 2.
(2)
At the same time, Device B transmits Seg_S, Seg_T, and Seg_U to Port 1.
(3)
Device A properly receives Seg_A, but detects an error with Seg_B.
(4)
Device B returns positive acknowledge for Seg_A, but requests retransmission of
Seg_B. Device B discards all subsequently received segments until Seg_B is
received again.
(5)
At the same time, Device A acknowledges the proper reception of Seg_S; Seg_T;
and Seg_U.
(6)
Device A resends all segments starting from Seg_B.
(7)
Finally, Device B acknowledges the proper reception of Seg_B and Seg_C.
Effect of Link Management Packet Corruption
If a retry-on-error link management packet is corrupted, it is discarded,
and the near transmitter times out waiting for acknowledgement of the
previously transmitted priority packet. When the timeout occurs, the
near transmitter retransmits all buffered packets.
Error Events &
Handling
The SerialLite II protocol classifies all errors as catastrophic, link, data, or
marked bad. A catastrophic error is an unrecoverable error caused by the
initialization state machines. A link error results when the link is not able
to transmit or receive data and it triggers the initialization process. A data
Seg_A; Seg_B;
Seg_C
ACK_S; ACK
_T; ACK_U
Seg_S; Se
g_T; Se
g_U
ACK_A;
NACK_
B
ACK_B;
ACK_C
Resend S
eg_B; Seg_C
1
5
6
7
3
4
2
Device A
Device B