Altera RapidIO II MegaCore Function - Manual (Page 212)

B–4 Appendix B: Differences Between RapidIO II MegaCore Function v12.1 and RapidIO MegaCore Function v12.1
RapidIO II MegaCore Function August 2014 Altera Corporation
User Guide
Transport layer
Tx scheduling
The Transport layer implements a modified
round-robin scheduling algorithm to determine the
next packet to accept among those available from
the Avalon-ST pass-throuh interface and the Logical
layer module. Status information from the Physical
layer determines whether the round-robin algorithm
considers all available packets, or considers only
available packets with a priority field value above a
specified threshold. This threshold can also be set
to allow no packets through, providing a temporary
backpressure mechanism for the Physical layer to
control input from the Transport layer.
The Transport layer implements a round-robin
scheduling algorithm to determine the next packet
to accept among those available from the Avalon-ST
pass-through interface and the Logical layer
modules. This algorithm does not consider the
priority field values of the packets.
Number of
Link-Request
Attempts
Before
Declaring
Fatal Error
parameter
The number of times that a RapidIO II IP core sends
a link-request input-status control symbol
following a link-request time-out, before
declaring a fatal error, is seven. This value cannot be
modified in the parameter editor.
The Link-request attempts parameter allows you to
specify the number of times the RapidIO IP core
sends a link-request input-status control
symbol following a link-request time-out, before
declaring a fatal error. This parameter can have
values 1 through 7. The default value in a new
variation is 7.
Sending
Link-Request
Reset-Device
on Fatal Errors
parameter
In the RapidIO II IP core, this parameter is not
available. If the RapidIO II IP core identifies a fatal
error, it notifies software by setting the PORT_ERR
bit in the Port 0 Error and Status CSR and
asserting the port_error output signal, which
may be used as an interrupt output signal. However,
it does not transmit link-request reset-
device
control symbols.
The Send link-request reset-device on fatal errors
option specifies that if the RapidIO IP core identifies
a fatal error, it transmits four link-request
control symbols with cmd set to reset-device on
the RapidIO link. By default, this option is turned
off. The option is available for backward
compatibility, because previous releases of the
RapidIO IP core implement this behavior.
In any case the RapidIO IP core notifies software by
setting the PORT_ERR bit in the Port 0 Error
and Status CSR
and asserting the port_error
output signal.
Table B–1. Major Differences Between the RapidIO II IP Core v12.1 and the RapidIO IP Core v12.1 (Part 4 of 4)
Property RapidIO II IP Core v12.1 RapidIO IP Core v12.1