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unaligned transfers

tom

Hi all

i have some questions.

Q1

if the master write a burst started in unaligned  address.
How to know the slave support unaligned transfers or not?


Q2
AXI spec mention that  the AXI protocol does not require the slave to take special action based on any alignment
information from the master.
what is the meaning of that?

Thanks a lot

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    Q1 - the protocol states that unaligned transfers are allowed (although not for WRAP bursts), so the slave MUST support them.

    However "support" could mean that the slave returns a SLVERR response, perhaps because unaligned transfers are incompatible with the function of the slave. The slave then has still accepted the transaction and has given a response.

    But unless the slave function has good reason to not support legal unaligned transfers, it should fully support them as there is no AXI defined way of telling masters not to use them.

    Q2 - I have absolutely no idea what this means.

    I suppose it could describe that the start address unalignment has no additional meaning other than the simple fact that the transaction start address is not AxSIZE aligned. 

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  • 0

    Q1 - the protocol states that unaligned transfers are allowed (although not for WRAP bursts), so the slave MUST support them.

    However "support" could mean that the slave returns a SLVERR response, perhaps because unaligned transfers are incompatible with the function of the slave. The slave then has still accepted the transaction and has given a response.

    But unless the slave function has good reason to not support legal unaligned transfers, it should fully support them as there is no AXI defined way of telling masters not to use them.

    Q2 - I have absolutely no idea what this means.

    I suppose it could describe that the start address unalignment has no additional meaning other than the simple fact that the transaction start address is not AxSIZE aligned. 

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