Apparatus and method for testing a memory array
First Claim
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1. An apparatus for testing a memory array comprising:
- a test data latch for receiving a test data vector on a serial input of said test data input latch and writing said test data vector in to a first location in said memory array;
an address buffer for receiving a test address vector on a serial input of said address buffer and applying said test address vector to said memory array;
an output latch for reading said test data vetor from said first location in said memory array; and
control logic for
1) scanning said test data vector and said test address vector into said test data input latch and said address buffer, respectively,
2) generating a write signal operable to cause said test data vector to be written from said test data input latch into said first lacation in said memory array and
3) generating a read signal operable to cause said test data vector to be read from said first location in said memory array into said output latch.
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Abstract
There is disclosed a central controller for simultaneously testing the embedded arrays in a processor. Test data vectors are serially shifted into a latch and stored into each location in the embedded arrays of the processor. The test data are then read out of the embedded arrays into a read latch and serially shifted into a multiple input shift register, where a polynomial division is performed on the test vector data. If all memory locations in the embedded array function properly, a remainder value will result that is equal to a unique signature remainder for the test vectors used.
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Citations
11 Claims
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1. An apparatus for testing a memory array comprising:
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a test data latch for receiving a test data vector on a serial input of said test data input latch and writing said test data vector in to a first location in said memory array; an address buffer for receiving a test address vector on a serial input of said address buffer and applying said test address vector to said memory array; an output latch for reading said test data vetor from said first location in said memory array; and control logic for
1) scanning said test data vector and said test address vector into said test data input latch and said address buffer, respectively,
2) generating a write signal operable to cause said test data vector to be written from said test data input latch into said first lacation in said memory array and
3) generating a read signal operable to cause said test data vector to be read from said first location in said memory array into said output latch. - View Dependent Claims (2, 3, 4)
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5. A processor comprising:
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N memory arrays; N test data input latches, each of said N test data input latches associated with a selected one of said N memory arrays, for receiving test data vectors on serial inputs of said N test data input latches and writing said test data vectors into a plurality of locations in said N memory arrays; N address buffers, each of said N address buffers associated with a selected one of said N memory arrays, for receiving test address vectors on serial inputs of said N address buffers and applying said test address vector to said N memory arrays; N output latches, each of said N output latches associated with a selected one of said N memory arrays, for reading said test data vectors from said plurality of locations in said N memory arrays; and control logic comprising; vector loading circuitry for scanning said test data vectors into said N test data input latches and scanning said test address vectors into said N address buffers; data write circuitry for generating a plurality of write signals operable to cause said test data vectors to be written from said N test data input latches into said plurality of locations in said N memory arrays; data read circuitry for generating a plurality of read signals operable to cause said test data vectors to be read from said plurality of locations in said N memory arrays into said N output latches. - View Dependent Claims (6, 7, 8, 9)
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10. A method of testing a memory array comprising the steps of:
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serially shifting a test data vector into a test data input latch; serially shifting a test address vector into an address buffer; applying the test address vector in the address buffer to the address lines of the memory array; writing the test data vector from the test data input latch into a first location in the memory array; reading the test data vector from the first location in the memory array into an output latch; serially shifting the test data vector from the output latch into a multiple input shift register; and performing a polynomial division operation using the shifted test data vector as an input to generate thereby a signature remainder indicating whether the first location in the memory array contains a fault. - View Dependent Claims (11)
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Specification