Altera RapidIO MegaCore Function User Manual
Page 104
4–58
Chapter 4: Functional Description
Logical Layer Modules
RapidIO MegaCore Function
August 2014
Altera Corporation
User Guide
In cycle 0, the user logic indicates to the RapidIO IP core that it is ready to receive a
packet transfer by asserting gen_rx_ready. In cycle 1, the IP core asserts gen_rx_valid
and gen_rx_startofpacket. During this cycle, gen_rx_size is valid and indicates that
five cycles are required to transfer the packet.
shows the RapidIO header
fields and the payload carried on the gen_rx_data bus in each cycle.
Table 4–15. RapidIO Header Fields and gen_rx_data Bus Payload (Part 1 of 2)
Cycle
Field
gen_rx_data bus
Value
Comment
1
ackID
[63:59]
5'h00
rsvd
[58:57]
2'h0
CRF
[56]
1'b0
prio
[55:54]
2'h0
tt
[53:52]
2'h0
Indicates 8-bit device IDs.
ftype
[51:48]
4'h5
A value of 5 indicates a Write Class packet.
destinationID
[47:40]
8'haa
sourceID
[39:32]
8'hcc
ttype
[31:28]
4'h4
The value of 4 indicates a NWRITE transaction.
wrsize
[27:24]
4'hc
The wrsize and wdptr values encode the
maximum size of the payload field. In this example,
they decode to a value of 32 bytes. For details, refer
to Table 4-4 in Part 1: Input/Output Logical
Specification of the RapidIO Interconnect
Specification, Revision 2.1
srcTID
[23:16]
8'h00
address[28:13]
[15:0]
16'h5a5a
The 29 bit address composed is
29’hb4b5959
.
This becomes
32'h5a5acac8
, the double-word
physical address.
2
address[12:0]
[63:51]
13'h1959
wdptr
[50]
1'b0
See description for the size field.
xamsbs
[49:48]
2'h0
Payload Byte0,1
[47:32]
16'h0001
Payload Byte2,3
[31:16]
16'h0203
Payload Byte4,5
[15:0]
16'h0405
3
Payload Byte6,7
[63:48]
16'h0607
Payload Byte8,9
[47:32]
16'h0809
Payload
Byte10,11
[31:16]
16'h0a0b
Payload
Byte12,13
[15:0]
16'h0c0d