Abstract:
A method of synchronizing the start of sequential read cycles when reading data in a memory in a synchronous mode with sequential access, using the increment pulses for at least an address counter of the memory cell array as synchronization signals, by generating, following each increment pulse, a dummy ATD pulse, undistinguishable from an ATD pulse generated upon detection of a switching of external address lines.
Abstract:
An interleaved memory readable in sequential access synchronous mode and in random access asynchronous mode, in function of external protocol signals ( ALE; CEn, RD ), has a circuit of internal regeneration of an external input address latch enabling signal ( ALE ), filtered by a second external chip enable signal ( CEn ). The circuit comprises a latch ( LATCH ) storing the external signal ( ALE_EXT ) of input address latch enabling and a NOR gate combining the output ( ALE_BUFF ) of the latch with the second external signal of chip enable ( CEn ) and producing a first internal replica signal of address latch enabling ( ALE_FAST ). Delay circuits in cascade to the output of the latch and in cascade of the input pad of the external signal of chip enable ( CEn ) and logic means combining the internally generated replica signal ( ALE_FAST ) and the signal ( ALE_BUFF ) present at the output of the latch with signals retarded by said delay circuits produce set and reset signals of an output flip-flop outputting a second internally generated reconditioned address latch enabling signal ( ALE ). The reconditioned signal has a raising edge conditionally retarded compared to the raising edge of the external command ( ALE_EXT ) and a duration that is conditionally incremented such to compensate for eventual critical asynchronisms between the two protocol external signals ( ALE_EXT, CEn ) in the different modes of operation of the interleaved memory.
Abstract:
An address binary counter for a subdivision bank of the cell array of an interleaved memory with burst access enabled by an enabling signal (ENABLE), comprises as many stages as the bits that may be stored in the cells of a row of the bank and a carry calculation network. The carry calculation network comprises an ordered group of independent carry generators, each of a certain number of stages, and having its own enabling bit, that are input with a number of consecutive bits of a row of the bank equal to the number of stages, orderly starting from the least significant bit. The enabling bit of the first carry generator of the ordered group is said enabling signal (ENABLE), and the enabling bit of any other carry generator of the ordered group is the logic AND of said enabling signal and of the input bits of the preceding carry generator of the ordered group.
Abstract:
An address binary counter for a subdivision bank of the cell array of an interleaved memory with burst access enabled by an enabling signal (ENABLE), comprises as many stages as the bits that may be stored in the cells of a row of the bank and a carry calculation network. The carry calculation network comprises an ordered group of independent carry generators, each of a certain number of stages, and having its own enabling bit, that are input with a number of consecutive bits of a row of the bank equal to the number of stages, orderly starting from the least significant bit. The enabling bit of the first carry generator of the ordered group is said enabling signal (ENABLE), and the enabling bit of any other carry generator of the ordered group is the logic AND of said enabling signal and of the input bits of the preceding carry generator of the ordered group.
Abstract:
The transfer of data within a system having a plurality of data sources (ASYNC BLOCK asynchronous and/or having different bitrates, to produce an output data stream (OUT) synchronous with a certain external timing signal (CLOCK, RD) of request of updating of the datum currently present at the output, is managed by a circuit that includes an output register (OUT REG) in which the datum to be made available at the output is stored and at least an output buffer (OUT BUFF) driving an external data line and functionally coupled to the output of said output register (OUT REG). Each data source (ASYN_BLOCK ) has a data loading register (REG ), a selection multiplexer (MUX) of data to be transferred from one or another of said loading registers to said output register (OUT REG). A central control unit (CPU) produces a plurality of control signals (START , REQ , PRIORITY , CLOCK, RD, GLOBAL_RESET). The circuit managing the transfer (SYNC_ASYN CONTROL) includes a plurality of identical circuits, each dedicated to one of said data sources and composed of a coincidence detecting circuit with hooking (COINCIDENCE DETECTOR WITH HOOKING) input with the logic end signal (PULSE) of said external timing signal (CLOCK RD) and of a selection signal (REQ ) of the source of the datum to be produced in output, and a confirmation signal (DATA_READY ) of availability of the datum at the output of said selected source, outputting in a stretching signal (OK_STR), and of a conditioned update path of the output datum constituted by a first bistable circuit (LATCH UPDATE FLAG) set by the inverted confirmation signal (DATA_READY ) and reset by the logic OR of a global reset command (GLOBAL_RESET) generated by the central control unit (CPU) and of the logic OR of the timing signal (CLOCK) and of the stretching signal (OK_STR), outputting a first flag (OK_UPDATE) of enablement of the updating; a second bistable circuit (ENABLING FLAG OF OUT REG UPDATE) set by the output of said detecting circuit and reset by the logic OR of the signal (GLOBAL_RESET) and of a signal (NEW_OUT) corresponding to the logic OR of signals (NEW_OUT ) coming from the respective data sources , outputting an update flag (PRE_LOAD); a logic OR gate, input with the update flag (PRE-LOAD) and with the logic OR signal of the signal (PULSE) and of the stretching signal (OK_STR) and producing in output a selection signal (LOAD ) for the multiplexer (MUX); a pass-gate coupling the input of an output buffer OUT BUFF to the respective output register OUT REG, enabled by the logic OR signal (NEW_OUT) of the signals (NEW_OUT ), each corresponding to the logic OR of the signal (PULSE) and of the stretching signal (OK_STR) of the managing circuit (block ) of a respective data source.
Abstract:
An interleaved data path and output management architecture for an interleaved memory, divided in at least a first bank and a second bank (EVEN BANK, ODD BANK) , each provided with an array of sense amplifiers (EVEN SENSE, ODD SENSE) and a register of read data (DATA OD REGISTER, DATA EV REGISTER) , and comprising an array of output buffers ( BUFFOUT) , controlled by external protocol signals (CE, OE) and a control and timing circuitry (TIMING) receiving as input external protocol signals (ALE, RD, CE) and producing enabling and/or path selection signals ( SAEN_EVEN, SAEN_ODD, SAlatch_EVEN, SAlatch_ODD, LOAD_EVEN, LOAD_ODD) , comprises:
at least a third register (DATA OUT REGISTER) to the inputs of which are fed the output data of said registers of data read from the two banks DATA EV REGISTER, DATA OD REGISTER) in function of path selection signals (LOAD_EVEN, LOAD_ODD) produced by said control and timing circuitry (TIMING) ; and an array of pass-gates controlled in common by a control signal (DLATCHN) generated by said control and timing circuitry b enabling the transfer of data stored in said third register (DATA OUT REGISTER) to respective inputs of said array of output buffers (BUFFOUT).
Abstract:
A multipurpose memory device suitable for a broader range of applications, whether requiring the reading of data in asynchronous mode with random access (as in a standard memory) or in synchronous sequential mode with sequential or burst type access, is capable of recognizing the mode of access and of reading that is currently required by the microprocessor and of self-conditioning its internal circuitry in function of such a recognition in order to read data in the requested mode without requiring the use of additional external control signals and/or implying a penalization in terms of access time and reading time compared to those which, for the same fabrication technology and state of the art design, may be attained with memory devices specifically designed for either one or the other mode of operation.