Achronix Speedster22i Interlaken - Manual (Page 32)

This signal is asserted for one clock period each time a CRC24 error is detected.
stat_rx_msop_err
Packets received with a particular channel address must begin with a valid Start-of-Packet (SOP).
If data is detected for a particular channel without a valid SOP, this signal is asserted for a single
Local bus clock cycle. Additionally, the required SOP is inserted before the data and an error is
signaled in the End-of-Packet (EOP) cycle via the rx_errout signal.
This signal is available as a status signal to indicate a missing SOP error condition occurred. No
indication is provided on the Local bus which packet had the missing SOP. The packet is simply
marked as containing an error. This is because a missing SOP is almost always associated with
other errors that cannot be associated with a particular packet.
The purpose of SOP insertion is to ensure that packets for a particular channel are always
delivered on the RX Local bus with the beginning with an SOP and ending with an EOP to
remove the need for user logic to perform bus protocol checking. The stat_rx_msop_err status
signal indicates that this function is being performed and for most applications can be ignored.
stat_rx_meop_err
Packets received with a particular channel address must begin with a valid Start-of-Packet (SOP)
and end with a valid End-of-Packet (EOP). If an SOP is detected without receiving an EOP for the
previous packet, this signal is asserted for a single Local bus clock cycle. Additionally, the extra
SOP is deleted, the packets are merged together, and an error is signaled with the End-of-Packet
(EOP) via the rx_errout signal.
This signal is available as a status signal to indicate a missing EOP error condition occurred and
that SOP deletion occurred. No indication is provided on the Local bus which packet is actually a
merged packet. The packet is simply marked as containing an error. This is because a missing
EOP is almost always associated with other errors that cannot be associated with a particular
packet.
The purpose of SOP deletion is to ensure that packets for a particular channel are always
delivered on the RX Local bus with the beginning with an SOP and ending with an EOP to
remove the need for user logic to perform bus protocol checking. The stat_rx_meop_err status
signal indicates that this function is being performed and for most applications can be ignored.
stat_rx_burst_err
This signal is asserted if:
1. A BurstShort violation is detected, or
2. A burst length violation is detected.
When this signal is a value of 1, it indicates one of the above burst errors has been detected. These
errors are treated like a CRC24 error and all open packets are treated as being in error.
This signal is asserted for one clock period each time an error is detected.
A BurstShort error occurs when the spacing between Burst Control Words is less than the
ctl_tx_burstshort parameter. A burst length violation occurs when the length of a received burst,
other than those ending with an End-of-Packet, is not a multiple of the RX LBUS width.
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