Altera RapidIO II MegaCore Function - Manual (Page 59)

Chapter 4: Functional Description 4–17
Logical Layer Interfaces
August 2014 Altera Corporation RapidIO II MegaCore Function
User Guide
Table 4–8 lists the write-request conversions the RapidIO II IP core performs for
RapidIO write request packets with wrsize value greater than 4’b1011.
Input/Output Avalon-MM Master Module Timing Diagrams
Figure 4–6 shows the timing dependencies on the Avalon-MM master interface for an
incoming RapidIO NREAD transaction. Figure 4–7 shows the timing dependencies on
the Avalon-MM master interface for an incoming RapidIO NWRITE transaction.
1011
0
0 1 0000_0000_1111_1111
1 1 1111_1111_0000_0000
1
0 1 1111_1111_1111_1111
1 2 (2)
Notes to Table 4–7 :
(1) The RapidIO link partner should avoid this combination of wdptr and wrsize values, because the resulting
byteenable value presented on the Avalon-MM master interface is not allowed by the Avalon-MM specification.
(2) When wrsize has the value of 1011, wdptr has the value of 1, and address[0] has the value of 1, the byteenable
value presented on the Avalon-MM master interface in the first clock cycle is 16’b1111_1111_0000_0000, and the
byteenable value presented on the second cycle is 16’b0000_0000_1111_1111.
Table 4–7. Avalon-MM I/O Master Write Transaction Burstcount and Byteenable I (Part 3 of 3)
RapidIO Field Values Avalon-MM Signal Values
wrsize
(4'bxxxx)
wdptr
(1'bx)
address[0]
(1'bx)
Burstcount Byteenable (16'bxxxx_xxxx_xxxx_xxxx)
Table 4–8. Avalon-MM I/O Master Write Transaction Burstcount and Byteenable II
RapidIO Values Avalon-MM Signal Values
RapidIO Field Values Payload
Size is
Multiple
of 16
Bytes (1)
Burstcount
Byteenable (16'hXXXX)
wrsize
(4'bxxxx)
address[0]
(1'bx)
First Cycle
Intermediate
Cycles
Final Cycle
1100–1111
0
Yes
Payload size in bytes
/ 16
FFFF FFFF FFFF
1
Payload size in bytes
/ 16
plus 1
FF00 FFFF 00FF
0
No (2)
FFFF FFFF 00FF
1 FF00 FFFF FFFF
Note to Table 4–8 :
(1) If the packet payload is larger than the maximum size allowed for the packet wrsize and wdptr values, the RapidIO II IP core records an Illegal
transaction decode error in the Error Management Extension registers and, for NWRITE_R request packets, returns an ERROR response.
(2) If the payload size is not a multiple of 16 bytes, and address[0] has the value of zero, the value of burstcount is the number of 8-byte words
in the packet payload, divided by two, and rounded up.