Memory apparatus and data read method
A memory apparatus of an embodiment includes a nonvolatile semiconductor memory device, an error correction circuit, a memory circuit, a data distribution circuit, and a processing circuit. The error correction circuit performs error detection in data read from the nonvolatile semiconductor memory device on a processing unit size basis and performs error correction on the data in response to its necessity. The memory circuit stores data on the processing unit size basis. The data distribution circuit transfers the data read from the nonvolatile semiconductor memory device to the error detection circuit and the memory circuit on the processing unit size basis. The processing circuit reads the data from the memory circuit and processes the data in response to the error correction circuit detecting an uncorrectable error in the data.
1. A memory apparatus, comprising:
a nonvolatile semiconductor memory device;
an error correction circuit configured to
perform error detection in first data on a processing unit size basis, and
perform error correction on the first data in response to its necessity;
a memory circuit configured to store second data on the processing unit size basis;
a data distribution circuit configured to:
transfer third data read from the nonvolatile semiconductor memory device to the error correction circuit as the first data and
transfer the third data to the memory circuit as the second data on the processing unit size basis; and
a processing circuit configured to read the second data from the memory circuit and process the second data in response to the error correction circuit detecting an uncorrectable error in the first data.
2. The apparatus according to claim 1 , wherein the processing circuit reads the second data from the memory circuit and outputs the second data to an external device.
3. The apparatus according to claim 1 , wherein the processing circuit reads the second data from the memory circuit and stores the second data in the nonvolatile semiconductor memory device.
4. The apparatus according to claim 2 , wherein the processing circuit reads the second data from the memory circuit and outputs the second data to the external device, in response to a request from the external device.
5. The apparatus according to claim 3 , wherein the processing circuit reads the second data from the nonvolatile semiconductor memory device and outputs the second data to the external device, in response to a request from the external device.
6. The apparatus according to claim 1 , wherein the processing circuit includes:
a count circuit configured to count the number of “0” or “1” in the second data; and
a determination circuit configured to:
determine the nonvolatile semiconductor memory device having an operation abnormality in response to the number counted by the count circuit or/and a bit array of the second data satisfying a bias condition, and
determine data degradation at a time of read in response to the number or/and the bit array not satisfying the bias condition.
7. The apparatus according to claim 6 , wherein the determination circuit generates abnormality history information indicating determined result.
8. The apparatus according to claim 7 , wherein the abnormality history information is output to an external device in response to a request from the external device.
9. A memory apparatus comprising:
a nonvolatile semiconductor memory device;
an error correction circuit configured to:
perform error detection in first data read from the nonvolatile semiconductor memory device on a processing unit size basis,
perform error correction on the first data in response to its necessity, and
store the error-corrected first data in a data buffer as second data for outputting to an external device;
a data distribution circuit configured to:
store third data read from the nonvolatile semiconductor memory device into the data buffer without error correction when the error correction circuit detects an uncorrectable error in the first data; and
a processing circuit configured to read the third data stored in the data buffer and process the third data.
10. A data read method comprising:
reading first data from a nonvolatile semiconductor memory device;
transferring the first data to an error correction circuit as second data and transferring the first data to a memory circuit as third data on a processing unit size basis;
performing error detection in the second data transferred to the error correction circuit and performing error correction on the second data in response to its necessity; and
reading the third data stored in the memory circuit and processing the third data in response to detection of an uncorrectable error in the second data.
11. The method according to claim 10 , further comprising:
storing the third data in the nonvolatile semiconductor memory device in response to detection of an uncorrectable error in the second data; and
reading the third data stored in the memory circuit and processing the third data in response to a request from an external device.