11.6.1. BERROR

The BERROR signal is sampled on the risingedgeof BCLK during a sequential cycle, on both read and write accesses. The effect of BERROR on the operation of the ARM720T is discussed in Exceptions.

BERROR can be flagged on any sequential cycle; however, it is ignored on buffered writes, which cannot be aborted.

Linefetches

The effect of BERROR during linefetches is slightly different to that during other access.During a linefetch the ARM720T fetches four words of data, regardless of which words of data were requested by the ARM core, and the rest of the words are fetched speculatively.

  • If BERROR is asserted on a word which was requested by the ARM core, the abort functions normally.

  • If the abort is signalled on a word which was not requested by the ARM core, the access is not aborted, and program flow is not interrupted.

Regardless of which word was aborted, the line of data is not placed in the cache as it is assumed to contain invalid data.

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