Abstract: A method is provided for testing an integrated circuit comprising multiple cores, with at least two cores having different associated first and second clock signals of different frequencies. A test signal is provided using a clocked scan chain clocked at a test frequency (TCK). A transition is provided in a clock circuit reset signal (clockdiv_rst) which triggers the operation of a clock divider circuit (44) which derives the first and second clock signals (clk_xx, clk_yy, clk_zz) from an internal clock (40) of the integrated circuit. The first and second clock signals thus start at substantially the same time, and these are used during a test mode to perform a test of the integrated circuit. After test, the test result is output using the clocked scan chain clocked at the test frequency (TCK).

Abstract: A method is provided for testing an integrated circuit comprising multiple cores, with at least two cores having different associated first and second clock signals of different frequencies. A test signal is provided using a clocked scan chain clocked at a test frequency (TCK). A transition is provided in a clock circuit reset signal (clockdiv_rst) which triggers the operation of a clock divider circuit (44) which derives the first and second clock signals (clk_xx, clk_yy, clk_zz) from an internal clock (40) of the integrated circuit. The first and second clock signals thus start at substantially the same time, and these are used during a test mode to perform a test of the integrated circuit. After test, the test result is output using the clocked scan chain clocked at the test frequency (TCK).

Abstract: The invention relates to an integrated circuit, comprising a number of independent clock domains. Seam circuits are provided in the interface signals paths between the clock domains in order to be able to isolate clock domains from each other during testing. Each seam circuit comprises a feedback loop having a multiplexer and a flip-flop feeding a first input of the multiplexer, a second input of the multiplexer being connected to the seam input, an output of the feedback loop being connected to the output; so that a first state of the multiplexer allows loading of a data bit in the feedback loop via the seam input, and a second state of the multiplexer freezes the data bit in the feedback loop.