Abstract: A semiconductor memory has a field programmable unit in which logic to inter-convert external signals to be input/output to/from a memory system and internal signals to be input/output to/from a memory cell array is programmed. A program for constructing the logic of the field programmable unit is stored in a nonvolatile program memory unit. Through the field programmable unit, a controller can access the memory cell array, even when the interface of the controller accessing the semiconductor memory is different from an interface for accessing the memory cell array. Therefore, one kind of semiconductor memory can be used as plural kinds of semiconductor memories. This eliminates the need to develop plural kinds of semiconductor memories, reducing a development cost.

Abstract: A conversion control unit sets a converting function of a write data conversion unit or a read data conversion unit enabled or disabled for each controller. Accordingly, for a controller which needs original external data, the external data can be inputted and outputted, whereas for a controller which needs converted internal data, the internal data can be inputted and outputted. A data converting function of a conventional controller can be realized in a semiconductor memory, which can reduce the load on the controller. As a result, the performance of a system can be improved. A disabled controller which has no access right cannot read correct data (original data before conversion). Hence, the security of data written into the semiconductor memory can be protected.

Abstract: A controller converts a parallel command signal and address signal, or a parallel write data signal into a first serial signal, and outputs the converted signal as a first optical signal with a single wavelength to a memory device via an optical transmission line. The memory device converts the first optical signal into the original parallel command signal, address signal, and write data signal, and outputs the converted parallel signals to a memory unit. The memory device converts a parallel read data signal from the memory unit into a second serial signal, and outputs the converted signal to the controller via the optical transmission line as a second optical signal with a single wavelength. It is unnecessary to transmit the optical signal using an optical multiplexer, an optical demultiplexer, etc., thereby improving transmission rate of signals transmitted between the controller and the memory device at minimum cost.

Abstract: A memory controller multiplexes access signals each consisting of a plurality of bits as optical signals and outputs the multiplexed optical signals. At this time, the optical signals whose wavelengths differ depending on memory devices are generated. A memory interface unit demultiplexes the multiplexed optical signals into the original optical signals and converts the demultiplexed optical signals into electrical signals. The memory interface unit determines to which of the memory devices the electrical signals resulting from the conversion should be outputted, according to the wavelengths of the demultiplexed optical signals. This frees the memory controller from a need for transmitting to the memory interface unit a signal for identifying the memory device. The memory interface unit need not include a decoding circuit for identifying the memory device.

Abstract: A controller converts a parallel command signal and address signal, or a parallel write data signal into a first serial signal, and outputs the converted signal as a first optical signal with a single wavelength to a memory device via an optical transmission line. The memory device converts the first optical signal into the original parallel command signal, address signal, and write data signal, and outputs the converted parallel signals to a memory unit. The memory device converts a parallel read data signal from the memory unit into a second serial signal, and outputs the converted signal to the controller via the optical transmission line as a second optical signal with a single wavelength. It is unnecessary to transmit the optical signal using an optical multiplexer, an optical demultiplexer, etc., thereby improving transmission rate of signals transmitted between the controller and the memory device at minimum cost.

Abstract: A memory cell array ARY includes a plurality of sub-arrays SARY. A data transfer unit DTU alternately accesses the sub-arrays SARY to transfer data between the sub-arrays SARY. Accordingly, it is possible to transfer data stored in one of the sub-arrays SARY to another sub-array SARY without outputting the data to a bus connected to a semiconductor memory MEM. For example, a microcontroller CNT in a system MSYS can use the bus during the data transfer since the bus is not used for the data transfer. As a result, it is possible to prevent the performance of the system MSYS from being deteriorated due to the data transfer.

Abstract: A conversion control unit sets a converting function of a write data conversion unit or a read data conversion unit enabled or disabled for each controller. Accordingly, for a controller which needs original external data, the external data can be inputted and outputted, whereas for a controller which needs converted internal data, the internal data can be inputted and outputted. A data converting function of a conventional controller can be realized in a semiconductor memory, which can reduce the load on the controller. As a result, the performance of a system can be improved. A disabled controller which has no access right cannot read correct data (original data before conversion). Hence, the security of data written into the semiconductor memory can be protected.

Abstract: A semiconductor memory has a field programmable unit in which logic to inter-convert external signals to be input/output to/from a memory system and internal signals to be input/output to/from a memory cell array is programmed. A program for constructing the logic of the field programmable unit is stored in a nonvolatile program memory unit. Through the field programmable unit, a controller can access the memory cell array, even when the interface of the controller accessing the semiconductor memory is different from an interface for accessing the memory cell array. Therefore, one kind of semiconductor memory can be used as plural kinds of semiconductor memories. This eliminates the need to develop plural kinds of semiconductor memories, reducing a development cost.

Abstract: A memory controller multiplexes access signals each consisting of a plurality of bits as optical signals and outputs the multiplexed optical signals. At this time, the optical signals whose wavelengths differ depending on memory devices are generated. A memory interface unit demultiplexes the multiplexed optical signals into the original optical signals and converts the demultiplexed optical signals into electrical signals. The memory interface unit determines to which of the memory devices the electrical signals resulting from the conversion should be outputted, according to the wavelengths of the demultiplexed optical signals. This frees the memory controller from a need for transmitting to the memory interface unit a signal for identifying the memory device. The memory interface unit need not include a decoding circuit for identifying the memory device.

Abstract: A semiconductor integrated circuit device having internal circuits, and a test mode selecting circuit. The selecting circuit includes a first load device, a transistor having a first terminal receiving a signal via the first load device, a control terminal receiving a first voltage and a second terminal, and a second load device provided between the second terminal of the transistor and a reference voltage node. A test mode selecting signal is output via the second terminal of the transistor when a second voltage higher than the voltage of the signal applied to the first load device in a normal operation mode is applied thereto. The test mode selecting signal is applied to predetermined internal circuits among said internal circuits, so that the predetermined internal circuits are switched to states of a test mode from the normal operation mode.

Abstract: A semiconductor memory device includes a memory cell array formed of a plurality of memory cells, a peripheral circuit supplied with address signals for selecting a memory cell in the memory cell array, the peripheral circuit further conducting a reading of the content of information stored in the selected memory cell and producing an output indicative thereof, and an address transition detection circuit for detecting a transition in any of the address signals and further for detecting a transition of the output of the peripheral circuit, wherein the address transition detection circuit activates the peripheral circuit when a transition has occurred in any of the address signals and the output of the peripheral circuit.

Abstract: A semiconductor memory device includes a plurality of memory cells arranged in a matrix form and a decoder circuit selecting a row of the matrix in response to an address signal. The decoder circuit includes a first-stage decoder having a plurality of first-stage decoding elements and a second-stage decoder having a plurality of second-stage decoding elements. Each first-stage decoding element is connected to a plurality of second-stage decoding elements. Each of the first-stage decoding elements receives predetermined higher bits of the address signals. One of the first-stage decoding elements is selected upon one access command. Each of the plurality of second-stage decoding elements receives the address signals. One of the rows of the matrix is selected in response to the the address signals when the corresponding first-stage decoding element operates, whereby the power consumption is reduced.