Always-On Audio Control for Mobile Device

A system comprising:

• an audio input device;
• an audio coder/decoder (codec) coupled to the audio input device and configured to generate audio samples from sound detected by the audio input device;
• a memory;
• and
• an integrated circuit coupled to the audio codec and the memory, wherein the integrated circuit includes an audio filter, one or more processors, and a memory controller coupled to the memory;
• the audio filter is configured to detect a predetermined pattern in the audio samples from the audio codec during a time that the memory controller and the one or more processors are powered down and is configured to cause the memory controller and the one or more processors to power up responsive to detecting the predetermined pattern;
• and
• the audio filter is configured to:
• buffer the audio samples that match the pattern and subsequently-received samples while the memory controller initializes, write the audio samples that match the predetermined pattern and the subsequently-received samples to memory through the memory controller, and continue writing audio samples received after the memory controller initializes, providing a loss-free series of samples beginning with at least the audio samples that match the predetermined pattern for processing by the one or more processors.

A method comprising:

• receiving audio samples captured by one or more audio input devices in a first circuit in an integrated circuit;
• detecting a predetermined pattern in the audio samples by the first circuit during a time that one or more processors in the integrated circuit and a memory controller in the integrated circuit are powered down;
• causing the memory controller and the one or more processors to power up responsive to detecting the predetermined pattern;
• buffering the audio samples that match the pattern and subsequently-received samples in the first circuit while the memory controller initializes;
• writing the audio samples that match the predetermined pattern and the subsequently-received samples from the first circuit to memory through the memory controller;
• and
• continuing to write audio samples received after the memory controller initializes from the first circuit to the memory through the memory controller, providing a loss-free series of samples beginning with at least the audio samples that match the predetermined pattern for processing by the one or more processors.