Altera POS-PHY Level 4 IP Core User Manual
Page 57
Chapter 4: Functional Description—Receiver
4–19
Error Flagging and Handling
December 2014
Altera Corporation
POS-PHY Level 4 IP Core User Guide
Table 4–4
summarizes the errors.
Table 4–4. Atlantic Error Handling (Part 1 of 2)
Error
Condition
Response
Missing SOP
■
Packet is not open.
■
End of packet (EOP) without
preceding SOP.
■
Data belonging to unopened
packet is discarded.
■
When it detects a missing SOP error, the Atlantic
FIFO buffer error checker block asserts the
err_ry_msopN
flag.
■
Data following a missing SOP is ignored for that
port until an EOP is detected.
■
Drops data not preceded by a SOP (data is not
readable via the Atlantic interface).
.
Missing EOP
■
Multiple packets are open.
■
SOP without a preceding EOP.
■
Data subsequent to the
detection of multiple open
packets is discarded until an
EOP is detected.
■
Assert err_ry_meopN for one clock cycle. When
it detects a missing EOP error, the open packet is
closed by forcing an EOP into the buffer and
marking it with an error. When it is received on
the user Atlantic interface side, the aN_arxerr
and aN_arxeop signals are asserted.
■
The stat_ry_mp_erradr signal contains the
address of the failing packet.
■
Subsequent data that is rejected until the EOP is
detected is not signaled by the err_ry_meopN
signal.
Empty non-zero
■
The aN_arxmty inputs must
be zero whenever the
aN_arxeop
signal is not
asserted.
■
If a new packet with a non-
zero value for MTY is received
without an EOP, all
subsequent data associated
with that address is ignored
until an EOP associated with
that address is received.
■
When it detects the error, the open packet is
closed.
■
Assert err_ry_meopN for one clock cycle by
forcing an EOP into the buffer and marking it with
an error. When it is received on the transmit side,
the aN_atxerr and aN_atxeop signals are
asserted.
■
The signal stat_ry_mp_erradr contains the
address of the failing packet.
■
Subsequent data that is rejected until the EOP is
detected is not signaled by the err_ry_meopN
signal.
■
If an EOP is forced, the aN_atxerr output signal
is asserted. Generally this signal can be ignored,
unless the aN_atxeop signal is also asserted.