Method and apparatus for fault injection

A fault injection circuit, comprising:

• a first storage element having a first input configured to receive fault injection data and a first output;
• logic circuitry that includes
• a second serial output and a second serial input coupled to a third serial output of a boundary scan chain having a
• first plurality of scan cells, wherein the logic circuitry is configured to receive data from the boundary scan chain;
• a first control circuit that alternatively selects between passing a second plurality of faults stored in the first storage element and passing a third plurality received data from the third serial output of boundary scan chain to the second serial output wherein the collection of the second plurality of faults and the third plurality of received data is less than or equal to the first plurality of scan cells and wherein the first control circuit is configured to inject second plurality of faults and the third plurality of received data into the second plurality of scan cells in a predetermined pattern, and
• a fourth input coupled to the first output of the first storage element;
• and
• a second storage element having a fifth input coupled to the second serial output of the logic circuitry and having an output coupled to a third serial input of the boundary scan chain.

A fault injection circuit, comprising:

• a first storage element having a first input configured to receive a first data and having a first output;
• a second storage element having second input configured to receive a second data and having a second output;
• logic circuitry that includes
• a third serial output and a third serial input coupled to a fourth serial output of a boundary scan chain, wherein the logic circuitry is configured to receive data from the boundary scan chain having a first plurality of scan cells;
• a first control input that alternatively selects between passing a second plurality of faults stored in the first storage element, passing a third plurality of faults stored in the second storage element, and passing a fourth plurality of received data from the fourth serial output of the boundary scan chain to the third serial output wherein the collection of the second plurality of faults, the third plurality of faults, and the fourth plurality of received data is less than or equal to the first first plurality of scan cells and wherein the second control circuit is configured to inject the second plurality of faults, the third plurality of faults, and the fourth plurality of received data into the first plurality of scan cells in a predetermined pattern,
• a fifth input coupled to the first output of the first storage element, and
• a sixth input coupled to the second output of the second storage element;
• and
• a third storage element having seventh input coupled to the third serial output of the logic circuitry and having an output coupled to a fourth serial input of the boundary scan chain.

A method for performing fault injection comprising:

• receiving circuit data received from a scan chain associated with a circuit wherein the scan chain has a first plurality of scan cells;
• generating a fault responsive to a first control signal;
• selectively passing a second plurality of faults and a third plurality of received circuit data to the first plurality of scan cells of the scan chain responsive to a second control signal wherein the collection of the second plurality of faults and the third plurality of received data is less than or equal to the first plurality of scan cells and wherein the second plurality of faults and the third plurality of received data are injected into first plurality of scan cells in a predetermined pattern;
• transmitting information stored in the scan chain storage element to logic circuitry.