Continuous application and decompression of test patterns and selective compaction of test responses
First Claim
1. A circuit, comprising:
- a parallel-in serial-out register; and
a decompressor comprising a phase shifter and a linear feedback shift register (LFSR), the LFSR being coupled between an output of the register and an input of the phase shifter,the parallel-in serial-out register being configured to load compressed test pattern bits in parallel and apply the compressed test pattern bits serially to the LFSR of the decompressor, andthe decompressor being configured to decompress the compressed test pattern bits into decompressed test pattern bits.
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Accused Products
Abstract
A method for applying test patterns to scan chains in a circuit-under-test. The method includes providing a compressed test pattern of bits; decompressing the compressed test pattern into a decompressed test pattern of bits as the compressed test pattern is being provided; and applying the decompressed test pattern to scan chains of the circuit-under-test. The actions of providing the compressed test pattern, decompressing the compressed test pattern, and applying the decompressed pattern are performed synchronously at the same or different clock rates, depending on the way in which the decompressed bits are to be generated. A circuit that performs the decompression includes a decompressor such as a linear finite state machine adapted to receive a compressed test pattern of bits. The decompressor decompresses the test pattern into a decompressed test pattern of bits as the compressed test pattern is being received.
162 Citations
9 Claims
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1. A circuit, comprising:
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a parallel-in serial-out register; and a decompressor comprising a phase shifter and a linear feedback shift register (LFSR), the LFSR being coupled between an output of the register and an input of the phase shifter, the parallel-in serial-out register being configured to load compressed test pattern bits in parallel and apply the compressed test pattern bits serially to the LFSR of the decompressor, and the decompressor being configured to decompress the compressed test pattern bits into decompressed test pattern bits. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification