When Wrapping happens in AXI?

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 楼主| 稻花香1号 发表于 2018-9-9 12:00 | 显示全部楼层 |阅读模式
pen, App, pi, AD, ST
Hi Forum,
I cannot understand when address is being wrapped in WRAP burst.In my example, the WRAP condition never happens in other words, during BURST operation address always remains small than wrap address.
From the spec, the wrapping happens when
        Address_N = Wrap_Boundary + (Number_Bytes × Burst_Length),\nAnd every new transfer for WRAP is defined as:
            Address_N = Aligned_Address + (N – 1) × Number_Bytes\nNow if we discuss this example:
Start_Address : 0x04  (d4):
awlen = 3  -> Burst_Length = 4
awsize = 1-> Number_Bytes=2
than we have:
Wrap Boundary = INT( d4/(24) )  (24) = INT(0.5)  8 = 1 *8 = 8
And Wrap Address: Address_N=Wrap_Boundary + (Number_Bytes × Burst_Length) = 8+(2*4) = 16
For the BURST:
Add1=4+ (1-1)*2 = 4
Add2=4+ (2-1)*2 = 6
Add3=4+ (3-1)*2 = 8
Add4=4+ (4-1)*2 = 10    -->  our Burst_length is 4, so BURST is ended no need to WRAP the address, so wrap conditions not happened.
Can someone please help me understand what I missed here? And what is the new address value after WRAP?
Thanks
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