This section describes examples of AXI conversion. In the examples, the green boxes represent unused data bytes and yellow boxes represent data bytes of interest.
In AXI conversion, because there could be upsizing from the AxSize of the master to the AxSize of the NoC, or upsizing from the AxSize of the NoC to the AxSize of the slave, read data over-fetch might occur in the NoC slave. It is assumed that read data over-fetch would not cause any side effect in the NoC slave. For write data, the NMU and NSU are responsible for creating correct write strobes.
In example 1, the NMU receives a request with AxBurst = WRAP and AxSize = 4 (128-bit). The request is transferred as is from the NMU through the NoC Channel to the NSU.
Example 1
WRAP (Behaves as non-modifiable INCR without downsize capability)
Applies to NoC Master / NoC Channel / NoC Slave
Start Addr \ Byte | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0x10 | ||||||||||||||||
0x20 | ||||||||||||||||
0x30 | ||||||||||||||||
0x00 |
Example 2
In Example 2, the NMU receives a request with AxBurst = WRAP and AxSize = 3 (64-bit). The request is converted to a modifiable/non-modifiable INCR burst in the NMU and is sent through the NoC channel to the NSU.
WRAP (converted to Modifiable/Non-modifiable INCR)
Start Addr \ Byte | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0x18 | ||||||||||||||||
0x20 | ||||||||||||||||
0x28 | ||||||||||||||||
0x30 | ||||||||||||||||
0x38 | ||||||||||||||||
0x00 | ||||||||||||||||
0x08 | ||||||||||||||||
0x10 |
Start Addr \ Byte | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0x00 | ||||||||||||||||
0x10 | ||||||||||||||||
0x20 | ||||||||||||||||
0x30 |
Start Addr \ Byte | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
---|---|---|---|---|---|---|---|---|
0x00 | ||||||||
0x08 | ||||||||
0x10 | ||||||||
0x18 | ||||||||
0x20 | ||||||||
0x28 | ||||||||
0x30 | ||||||||
0x38 |