Altera RapidIO II MegaCore Function User Manual
Page 84
4–42
Chapter 4: Functional Description
Logical Layer Interfaces
RapidIO II MegaCore Function
August 2014
Altera Corporation
User Guide
User Receiving MAINTENANCE Read Requests and Sending Responses
Table 4–21
lists the Maintenance Avalon-MM interface usage example this section
describes.
CRF
0
prio[1:0]
The IP core assigns to this field the value programmed in the PRIORITY field of
the Tx Maintenance Mapping Window n Control register (
) for the matching address translation window n. Refer to
“Defining
the Maintenance Address Translation Windows” on page 4–34
for matching
details.
tt[1:0]
2'b01
The value of 1 indicates 16-bit device IDs.
ftype[3:0]
4'b1000
The value of 8 indicates a Maintenance Class packet.
destinationID[15:0]
The IP core assigns to this field the value {LARGE_DESTINATION_ID,
DESTINATION_ID}
, based on the values programmed in the
LARGE_DESTINATION_ID
and DESTINATION_ID fields of the Tx
Maintenance Mapping Window n Control
register (
) for the matching address translation window n. Refer to
“Defining
the Maintenance Address Translation Windows” on page 4–34
for matching
details.
sourceID[15:0]
The IP core assigns to this field the value programmed in the
Large_base_deviceID
field of the Base Device ID register (offset 0x60).
ttype[3:0]
4’b0000
The value of 0 indicates a MAINTENANCE read request.
rdsize[3:0]
4'b1000
The size and wdptr values encode the maximum size of the payload field. In
MAINTENANCE
transactions, the value of wrsize is always 4’b1000, which
decodes to a value of 4 bytes. For encoding details, refer to Table 4-4 in Part 1:
Input/Output Logical Specification of the RapidIO Interconnect Specification,
Revision 2.2.
srcTID[7:0]
The RapidIO II IP core generates the source transaction ID value internally to
track the transaction response. The value depends on the current state of the
RapidIO II IP core when it prepares the RapidIO packet.
config_offset[20:0]
Depends on the values programmed in the Tx Maintenance Address
Translation Window
registers, as defined in
Refer to
“Defining the Maintenance Address Translation Windows” on
page 4–34
for the matching and conversion calculations.
wdptr
The IP core assigns to this field the negation of mnt_s_address[0].
hop_count
The IP core assigns to this field the value programmed in the HOP_COUNT field
of the Tx Maintenance Mapping Window n Control register (
) for the matching address translation window n. Refer to
“Defining the Maintenance Address Translation Windows” on page 4–34
for
matching details.
Table 4–20. Maintenance Read Request Transmit Example: RapidIO Packet Fields (Part 2 of 2)
Field
Value
Comment
Table 4–21. Maintenance Interface Usage Example: Receiving MAINTENANCE Read Request and
Sending Response
User Operation
Device ID Width
Payload Size
(Bytes)
Receive MAINTENANCE read request
16
0
Send MAINTENANCE read response
16
32