Abstract:
An electrically alterable semiconductor memory comprises at least two memory sectors (S1-S9) the content of which is individually alterable, and first control circuit means (4, 6) for controlling operations of electrical alteration of the content of the memory, capable of permitting the selective execution of an operation of electrical alteration of the content of one of said at least two memory sectors with the possibility of suspending said execution in order to permit read access to the other of said at least two memory sectors. The memory comprises second control circuit means (8, 6) capable of permitting, during said suspension, an operation of burst mode or page mode reading of the content of the other memory sector.
Abstract:
An autotesting method of a cells matrix of a memory device is disclosed which comprises the steps of:
reading the values contained in a plurality of the memory cells; comparing the read values with reference values; signalling mismatch of the read values with the reference values as an error situation; and storing the error situations.
In the autotesting method, the reading, comparing, signalling, and storing steps are repeated for all the memory cells in an matrix column. The autotesting method according to the invention further comprises the steps of:
storing the addresses of any columns having at least one error situation; and repeating all the preceding steps according to a step of scanning all the matrix columns.
Advantageously according to the invention, all said steps are internally realized in the memory device. Also disclosed is a memory device with a autotesting architecture, which device is adapted to implement the autotesting method according to the invention.
Abstract:
The output-buffer circuit (1) comprises an end stage (2) made up of a pull-up transistor (3) and a pull-down transistor (4) connected in series between a supply line (5) and a ground line (GND); a first driving stage (8) connected to a control terminal of the pull-up transistor (3) and comprising a plurality of first driving branches (12) which can be selectively activated by a logic control circuit (16) according to the reading and operating modes of a memory device (100) including the output-buffer circuit (1) and to the variability of the electrical parameters of the output-buffer circuit; and a second driving stage (9) connected to a control terminal of the pull-down transistor (4) and comprising a plurality of second driving branches (22) which can also be selectively activated by the control circuit (16) according to the reading and operating modes of a memory device (100) including the output-buffer circuit (1) and to the variability of the electrical parameters of the output-buffer circuit.
Abstract:
The invention relates to a read control circuit portion (1) and an attendant reading method for an electronic memory device (2) integrated in a semiconductor and including a non-volatile memory matrix (4) with associated row and column decoders (5,6) connected to respective outputs of an address counter (7), an ATD circuit (12) for detecting an input transaction as the memory device is being accessed, and read amplifiers (8) and attendant registers (10) for transferring the data read from the memory (2) to the output. The control circuit portion (1) comprises a detection circuit block (15) which is input a clock signal (CK) and a logic signal (BAN) to enable reading in the burst mode, and a burst read mode control logic (3) connected downstream of the circuit block (15). The method of this invention comprises accessing the memory matrix in a random read mode; detecting a request for access in the burst read mode; and executing the parallel reading of a plurality of memory words during a single period of time clocked by a clock signal (CK).