Context save and restore using test scan chains

A method for providing context save and restore using a test scan chain in an integrated circuit device also having a memory and a state machine, the method comprising:

• providing a scan chain of digital logic components comprised of a plurality of sub-chains;
• in a test mode,
• providing an input test data set to the scan chain, and
• scanning the input test data set through the scan chain, and
• providing an output test data set as an output of the scan chain;
• in a first switch mode,
• linking the sub-chains in parallel with each other and to a device memory, and
• reading a first functional data set from the memory;
• in a functional mode,
• linking the digital logic components with other logic circuitry in accordance with an application to be executed by the state machine, and
• executing the application to generate second functional data;
• and
• in a second switch mode,
• linking the sub-chains in parallel with each other and to the memory;
• storing the second functional data set in the memory.