Packets received with a particular channel address must begin with a valid 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 EOP cycle by the RX_ERROUT signal.
This signal is available as a status signal to indicate that a missing SOP error condition occurred. No indication is provided on the Local bus as to which packet had the missing SOP. The packet is 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 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.