
4–34 Chapter 4: Functional Description
Logical Layer Interfaces
RapidIO II MegaCore Function August 2014 Altera Corporation
User Guide
Table 4–14 lists the Maintenance Avalon-MM interface master port signals.
Initiating MAINTENANCE Read and Write Transactions
To initiate a
MAINTENANCE
read or write transaction on the RapidIO link, your system
executes a read or write transfer on the Maintenance Avalon-MM slave interface.
Refer to “Maintenance Interface Transaction Examples” on page 4–38 for examples of
how the RapidIO II IP core converts Avalon-MM requests to RapidIO
MAINTENANCE
request packets.
IP Core Actions
In response to incoming Avalon-MM requests to the Maintenance module slave
interface, the RapidIO II IP core Maintenance module generates
MAINTENANCE
requests
on the RapidIO link, by performing the following tasks:
■ For each incoming Avalon-MM read request, composes the RapidIO
MAINTENANCE
read request packet
■ For each incoming Avalon-MM write request, composes the RapidIO
MAINTENANCE
write request packet
■ Maintains status related to the composed
MAINTENANCE
packet to track responses
■ Presents the composed
MAINTENANCE
packet to the Transport layer for transmission
on the RapidIO link
1 At any time, the Maintenance module can maintain a maximum of 64 outstanding
MAINTENANCE
requests that can be
MAINTENANCE
reads,
MAINTENANCE
writes, or
port-write
requests. The Maintenance module slave port asserts the
mnt_s_waitrequest
signal to throttle incoming requests above the limit.
Defining the Maintenance Address Translation Windows
Two address translation windows available for interpreting incoming Avalon-MM
requests to the Maintenance module slave interface.
You must program the Tx Maintenance Window registers to support the address
ranges you wish to distinguish. The RapidIO II IP core Maintenance module
populates the following RapidIO Type 8 Request packet fields with values you
program for the relevant address translation window:
■
prio
■
destinationID
Table 4–14. Maintenance Avalon-MM Master Interface Signals
Signal Direction Description
usr_mnt_waitrequest
Input Maintenance master wait request.
usr_mnt_read
Output Maintenance master read request.
usr_mnt_write
Output Maintenance master write request.
usr_mnt_address[31:0]
Output Maintenance master address bus.
usr_mnt_writedata[31:0]
Output Maintenance master write data bus.
usr_mnt_readdata[31:0]
Input Maintenance master read data bus.
usr_mnt_readdatavalid
Input Maintenance master read data valid.
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