Method and apparatus to improve read reliability in semiconductor memories
First Claim
1. A method for controlling a period during which the output circuitry of a memory array waits before latching the output data comprising the steps of:
- selecting an address to be read from the memory array,providing a signal to initiate a read operation at the selected address,latching output data provided by the read operation at the selected address after a first predetermined period,interrogating the data latched to detect the presence of an error in the data read from the memory array,continuing the operation of reading data at any next address following the selected address if the presence of an error is not detected, andrepeating the operation of reading data at the selected address if the presence of an error is detected with output data being latched after a second longer predetermined period.
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Accused Products
Abstract
Apparatus for controlling a length of a period during which the output circuitry of a memory array waits before latching the output data including apparatus for detecting the presence of an error in data read from an memory array, apparatus for providing a first value to determine a wait period, apparatus responsive to the detection of an error for providing a second value, apparatus responsive to the first value for generating a signal to latch a data output from the memory array after a first period and responsive to the second value for generating a signal to latch a data output from the memory array after a second period.
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Citations
12 Claims
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1. A method for controlling a period during which the output circuitry of a memory array waits before latching the output data comprising the steps of:
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selecting an address to be read from the memory array, providing a signal to initiate a read operation at the selected address, latching output data provided by the read operation at the selected address after a first predetermined period, interrogating the data latched to detect the presence of an error in the data read from the memory array, continuing the operation of reading data at any next address following the selected address if the presence of an error is not detected, and repeating the operation of reading data at the selected address if the presence of an error is detected with output data being latched after a second longer predetermined period. - View Dependent Claims (2)
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3. A method for controlling a period during which the output circuitry of a memory array waits before latching the output data comprising the steps of;
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interrogating a selected address of a memory array to read data thereat, latching data read from the selected address after a first preselected period, examining the data latched using error detecting means to determine whether an error has occurred in the data read, utilizing the data read if no error has occurred, and repeating the process of interrogation of the selected address to read data thereat if an error has occurred in the data read while latching data read from the selected address after a period longer than the first preselected period. - View Dependent Claims (4)
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5. Apparatus for reading data from a memory array comprising:
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means for selecting an address to be read from the memory array, means for providing a signal to initiate a read operation at the selected address, means for latching output data provided by the read operation at the selected address after a first predetermined period, means for interrogating the data latched to detect the presence of an error in the data read from the memory array, means for continuing the operation of reading data at any next address following the selected address if the presence of an error is not detected, and means for repeating the operation of reading data at the selected address if the presence of an error is detected with output data being latched after a second longer predetermined period. - View Dependent Claims (6, 7, 8)
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9. Apparatus for reading data from a memory array comprising:
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circuitry for selecting an address to be read from the memory array; circuitry for providing a signal to initiate a read operation at the selected address; a data latch which latches output data provided by the read operation at the selected address after a first predetermined period; error detection circuitry for interrogating the data latched to detect the presence of an error in the data read from the memory array; circuitry for continuing the operation of reading data at any next address following the selected address if the presence of an error is not detected; and circuitry for repeating the operation of reading data at the selected address if the presence of an error is detected with output data being latched after a second longer predetermined period. - View Dependent Claims (10, 11, 12)
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Specification