US Patent 7346819 Through-core self-test with multiple loopbacks

An integrated circuit device having a test sequence generator, first and second transceivers and a test sequence analyzer. The test sequence generator generates a test data sequence in response to a test mode selection. The first transceiver receives the test data sequence from the test sequence generator and is configured in a loopback mode to transmit and receive the test data sequence. The second transceiver receives the test data sequence received by the first transceiver and is configured in a loopback mode to transmit and receive the test data sequence. The test sequence analyzer determines whether the test data sequence received by the second transceiver matches the test data sequence generated by the test sequence generator.