Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
88 words
A memory system comprising a storage unit (22), an ECC (error correcting code) generator (26) which generates an ECC which is stored in the memory unit with a data word, and error detection and correction circuitry (32,38,40, 42,20) which detects and corrects errors in a data word and associated ECC read from the storage unit, characterized in that the corrected data word and associated ECC bits are written back into the storage unit following each read, whereby the accumulation of errors in the data storage unit is inhibited.
Claim 2
Dependent Claim
88 words
A memory system comprising a storage unit (22), an ECC (error correcting code) generator (26) which generates an ECC which is stored in the memory unit with a data word, and error detection and correction circuitry (32,38,40, 42,20) which detects and corrects errors in a data word and associated ECC read from the storage unit, characterized in that the corrected data word and associated ECC bits are written back into the storage unit following each read, whereby the accumulation of errors in the data storage unit is inhibited.
Claim 3
Dependent Claim
60 words
A memory system according to Claim 1, characterized in that the error detection and correction circuitry comprises a comparator (32) fed with the ECC read from the storage unit and a fresh ECC generated from the data word read from the storage unit, and decoder means (38,40,42) which determines the location of any error in the data word and ECC.
Claim 4
Dependent Claim
29 words
A memory system according to Claim 2, characterized in that the decoder means includes a first level decoder (32) which determines whether or not an detected error is correctable.
Claim 5
Dependent Claim
42 words
A memory system according to Claim 3, characterized by second level decoder means (40,42) fed from the first level decoder (38) and comprising first (40) and second (42) decoders which decode the position of errors in the data word and ECC respectively.
Claim 6
Dependent Claim
42 words
A memory system according to any previous claim, characterized by internal timing and control means (12) responsive to instructions from an external source (2) to which the system is connected to control the operation of the system independently of the external source.