[GitHub] [incubator-nuttx] okayserh commented on pull request #6218: STM32F746G-Disco, Audiosupport, Bugfix

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okayserh commented on PR #6218:
URL: https://github.com/apache/incubator-nuttx/pull/6218#issuecomment-1126909941

   Note, I've further investigated the "clicking noise" mentioned above. Turned out that a D-Cache coherency issue caused this problem, which seems to have been specific to my development setup. If D-Cache is configured for write-through it works, without write-through an assertion should have caught this.
   What has happened in my understanding is, that after the DMA read, the cache was invalidated. However, since the buffer meta information is stored directly ahead of the actual sample data, updating this meta information can lead to overwriting the data that had just been read via DMA when the cache line is written back to memory. This affects only a few samples at the beginning of the buffer, creating the "clicking noise".


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