Ultra low pin count interface for die testing

A method comprising:

• communicating with an external tester to receive test data and to send test result using first and second communication modes;
• parsing the test data to extract microcode, the microcode containing a test program to test a circuit;
• loading the microcode to a memory;
• executing the test program;
• and
• providing the test result.

A system comprising:

• a tester;
• and
• a device under test (DUT) group coupled to the tester and having a plurality of dice, each of the dice having an ultra low pin count (ULPC) interface including a data signal and a dual-function signal, each of the dice comprising:
• an input/output (I/O) block to communicate with the tester to receive test data and to send test result on the data signal using first and second communication modes,
• a logic block coupled to the I/O block to parse the test data,
• a memory coupled to the logic block to store microcode from the parsed test data, the microcode containing a test program to test a circuit, and
• a controller coupled to the memory and the logic block to execute the test program.