Tap time division multiplexing
First Claim
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1. An integrated circuit comprising:
- a plurality of portions, each portion including test control circuitry;
at least one test input arranged to receive test data;
wherein said test data is clocked in a plurality of time slots, with test data for different ones of said plurality of portions being allocated to different time slots.
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Abstract
An integrated circuit comprising (i) a plurality of portions, each portion including test control circuitry; and (ii) at least one test input arranged to receive test data, wherein the test data is clocked in a plurality of time slots, with test data for different ones of the plurality of portions being allocated to different time slots.
24 Citations
26 Claims
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1. An integrated circuit comprising:
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a plurality of portions, each portion including test control circuitry; at least one test input arranged to receive test data; wherein said test data is clocked in a plurality of time slots, with test data for different ones of said plurality of portions being allocated to different time slots. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. An integrated circuit comprising:
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a plurality of portions, each portion including test control circuitry; and a plurality of test inputs arranged to receive test data, wherein in one mode of testing, data is transferred using tokens, with each token comprising m bits, m/2 bits being transferred on a rising edge of a clock signal and m/2 bits being transferred on a falling edge of a clock signal so that a token is transferred in a clock cycle. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. An integrated circuit having a first mode and a second mode of data transfer, wherein in the first mode of data transfer the time taken for a test data input from external test circuitry to be received and corresponding test data to be output to said external test circuitry is less than a clock period of said external test circuitry and in a second mode of data transfer the time taken for a test data input from external test circuitry to be received and corresponding test data to be output to said external test circuitry is greater than a clock period of said external test circuitry, said integrated circuit comprising:
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decoding means for decoding said test data input; target circuitry for interacting with said decoded test data input; and encoding means for encoding a signal from said target circuitry for said external test circuitry, wherein said circuit is arranged in both said first and second mode of data transfer to have a n cycle operation in which said decoding means decodes said signal, said target circuitry interacts which said signal and said encoding means encodes said signal. - View Dependent Claims (24)
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- 25. Test circuitry for testing an integrated circuit, said test circuitry being external to said integrated circuit, said integrated circuit having a first mode and a second mode of data transfer, wherein in the first mode of data transfer the time taken for test data input from said external test circuitry to be received and corresponding test data to be output to said external test circuitry is less than a clock period of said external test circuitry and in a second mode of data transfer the time taken for a test data input from external test circuitry to be received and corresponding test data to be output to said external test circuitry is greater than a clock period of said external test circuitry, said test circuitry having a plurality of buffer locations for buffering signals received from and/or sent to said test circuitry, wherein with the first mode of data transfer, the signals received from and/or sent to the test circuitry have a lower delay provided by said buffer locations than with the second mode of data transfer.
Specification