Wrapper selector data register having control outputs and SELECTAM input
A device test architecture and interface is provided to enable efficient testing embedded cores within devices. The test architecture interfaces to standard IEEE 1500 core test wrappers and provides high test data bandwidth to the wrappers from an external tester. The test architecture includes compare circuits that allow for comparison of test response data to be performed within the device. The test architecture further includes a memory for storing the results of the test response comparisons. The test architecture includes a programmable test controller to allow for various test control operations by simply inputting an instruction to the programmable test controller from the external tester. The test architecture includes a selector circuit for selecting a core for testing. Additional features and embodiments of the device test architectures are also disclosed.
1. An integrated circuit comprising:
A. core functional logic circuits; and
B. test wrapper circuitry coupled to the core functional logic, the test wrapper circuitry including an input bus, a control bus, and test access mechanism selector circuitry, the test access mechanism selector circuitry including:
i. a data register having an input coupled to the input bus;
ii. select outputs coupled to the data register;
iii. a scan router control output coupled to the data register;
iv. an other control output coupled to the data register;
v. a SELECTAM input coupled to the data register and to the input bus; and
vi. a clock input coupled to the data register and to the input bus.
2. The integrated circuit of claim 1 including decode circuitry coupled between the data register and all of the select outputs, the scan router control output, and the other control output.
3. The integrated circuit of claim 1 in which there is one select output for each core functional logic circuit.