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Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
16 years ago

No byte enable

Hi,

I am trying to create my own component using Avalon-MM. When I am generating sopc system I am getting following error:

Warning: 32-bit master connected to 128-bit slave with no byte enables (cpu/data_master -> mycomp_add/slave) at c:/altera/91/quartus//sopc_builder/bin/europa/europa_utils.pm line 248.

Can anyone suggest how to solve it?

Thanks,

Mumble.

2 Replies

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    16 years ago

    Correct, thats the only solution.

    Only byteenable signals tell the slave which byte (bits) should be modified and which should keep their content.
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    16 years ago

    Looks like you'd like a different answer than the one you've already been given in another post.

    The NIOS data master is 32-bits wide and it isn't going to get any bigger. Now the avalon interconnect fabric will handle adaptation between the NIOS' 32-bit master and your 128-bit slave. However, the way it does this is it addresses a portion of your 128-bit bus with each access. If you don't provide byte enables, each time the NIOS performs a 32-bit write to your slave, 96 of the 128 bits will get written with bogus data.

    The solution is to add byteenables to your slave.

    Jake