Memory self-test via a ring bus in a data processing apparatus

A method for processing data on a data processing apparatus operable in either a self-test mode or an operational mode, said method comprising the steps of:

• performing data processing operations using a plurality of functional units, at least one of said plurality of functional units being operable to perform data processing operations and at least a subset of said plurality of functional units having at least one of a respective co-processor register for storing configuration data, a respective debug register for storing debug data and a respective functional unit memory;
• outputting, in said self-test mode, self-test data for performing access operations to confirm correct operation of said functional unit memory;
• outputting debug data and co-ordinating debug operations;
• providing, in said operational mode, a first ring path for communication of configuration instructions between a ring sequence of said plurality of functional units;
• providing, in said operational mode, a second ring path for communication of said debug data between said ring sequence of said plurality of functional units;
• coupling said first ring-path and said second ring-path in said self-test mode to provide a combined data path for communication of self-test data between said plurality of functional units.

Apparatus for processing data, said apparatus being operable in a either a self-test mode or an operational mode, said apparatus comprising:

• a plurality of means for processing, at least one of said means for processing being operable to perform data processing operations and at least a subset of said plurality of means for processing having at least one of a respective means for storing configuration data, a respective means for storing debug data and a respective means for storing information;
• means for controlling memory self-test operations operable in said self-test mode to output self-test data for performing access operations to confirm correct operation of said means for storing information;
• means for communication of configuration instructions, arranged to provide in said operational mode, a ring path for communication of configuration instructions between a first ring sequence of said plurality of functional units;
• means for communication of debug data arranged to provide in said operational mode, a ring path for communication of debug data between a second ring sequence of said plurality of functional units;
• wherein said first ring sequence is identical to said second ring sequence and said data processing apparatus is operable in said self-test mode to couple said means for communication of configuration instructions and said means for communication of debug data to provide a combined data path for communication of self-test data between said plurality of functional units.