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First, second divided scan paths, adaptor, generator and compactor circuitry

  • US 10,060,977 B2
  • Filed: 06/06/2017
  • Issued: 08/28/2018
  • Est. Priority Date: 03/09/2000
  • Status: Expired due to Term
First Claim
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1. An integrated circuit comprising:

  • (a) logic circuitry including primary inputs, primary outputs, stimulus leads, and response leads;

    (b) scan path circuitry including a scan data input lead, a scan data output lead, and scan cells, each scan cell including;

    (i) multiplexer circuitry having a response input connected with one response lead, a scan data input, a scan enable input, and an output; and

    (ii) flip-flop circuitry having an input connected with the output of the multiplexer circuitry, a clock input, and a data output coupled with one stimulus bus lead;

    (c) a first scan path of serially connected scan cells that is selectably divided into a first part of scan cells and a second part of scan cells, a scan data input of the first scan cell in each part being coupled to the scan data input lead, and each part including an output buffer having a data input coupled with the data output of the last scan cell in the part, a buffer enable input, and a data output coupled with the scan data output lead;

    (d) a second scan path of serially connected scan cells that is selectably divided into a first part of scan cells and a second part of scan cells, a scan data input of the first scan cell in each part being coupled to the scan data input lead, and each part including an output buffer having a data input coupled with the data output of the last scan cell in the part, a buffer enable input, and a data output coupled with the scan data output lead;

    (e) adaptor circuitry having a first clock lead connected with the clock inputs of the first part of scan cells in the first and second scan paths, and a second clock lead connected with the clock inputs of the second part of scan cells in the first and second scan paths;

    (f) a test data generator circuit having control inputs and coupling the scan data input lead of the scan path circuit with the serial data inputs of the first scan path and the serial data inputs of the second scan path; and

    (g) a test data compactor circuit having control inputs and coupling the data output of the output buffers of the first scan path and the second scan path to the serial data output lead of the scan path circuit.

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