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changing endian in Avalon FIFO Memory

ASuba
Novice
561 Views

Hello

I am using Avalon FIFO memory with inout to AVALONMM_Memory mapped interface and Output conencted to AVALONST_Source. I find that the 32 bit days entering Memory mapped input is reversed bytewise with High endian converisona t output side.

1) Why is this so ?

2) Is there a possibility to change the behaviour and get the data as we send through the input side ?

 

-Athi

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1 Reply
GuaBin_N_Intel
Employee
153 Views
This is because by default, avalon FIFO's streaming interface has the properties "firstSymbolInHighOrderBits" set to be true. You can check it in Qsys>System contents by clicking on the streaming output. When it is true, data[31:24] will become D0 in data streaming https://www.intel.com/content/dam/www/programmable/us/en/pdfs/literature/manual/mnl_avalon_spec.pdf, Table 18. You could not change it as it is predefined setting in the IP. What you can do is to reverse the data symbol at output of Avalon-mm FIFO.
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