摘要:
To perform mask control of data signals without increasing the number of external terminals even when the number of bits in a data mask signal is large, an address input circuit sequentially receives a first address signal, a second address signal, and a first data mask signal supplied to an address terminal in synchronization with transition edges of a clock signal. Namely, the first data mask signal is supplied to the address terminal at a different timing from timing at which the first and second address signals are received. The first address signal, second address signal, and first data mask signal are output, for example, from a controller accessing a semiconductor memory. A data input/output circuit inputs/outputs data via a data terminal and masks at least either of write data to memory cells and read data from the memory cells in accordance with logic of the first data mask signal.
摘要:
To perform mask control of data signals without increasing the number of external terminals even when the number of bits in a data mask signal is large, an address input circuit sequentially receives a first address signal, a second address signal, and a first data mask signal supplied to an address terminal in synchronization with transition edges of a clock signal. Namely, the first data mask signal is supplied to the address terminal at a different timing from timing at which the first and second address signals are received. The first address signal, second address signal, and first data mask signal are output, for example, from a controller accessing a semiconductor memory. A data input/output circuit inputs/outputs data via a data terminal and masks at least either of write data to memory cells and read data from the memory cells in accordance with logic of the first data mask signal.
摘要:
An image memory, image memory system, and memory controller that are capable of efficiently accessing a rectangular area of two-dimensionally arrayed data are provided. The memory device has: a memory cell array that has a plurality of memory unit areas, each of which is selected by addresses; a plurality of input/output terminals; and an input/output unit provided between the memory cell array and the plurality of input/output terminals. Each of the memory unit areas stores therein data of a plurality of bytes or bits corresponding to the plurality of input/output terminals respectively, and the memory cell array and the input/output unit access a plurality of bytes or bits stored in a first memory unit area corresponding to the input address and in a second memory unit area adjacent to the first memory unit on the basis of the input address and combination information of the bytes or bits in response to a first operation code, and then, from the plurality of bytes or bits within the accessed first and second memory unit areas, associate a combination of the plurality of bytes or bits based on the combination information, with the plurality of input/output terminals.
摘要:
A semiconductor memory includes a refresh timer and an arbiter for determining the order of precedence between an access operation and a refresh operation, in order to automatically perform refresh operations inside the memory. A detecting circuit operates in a test mode and outputs a detection signal indicating that the refresh operation is yet to be performed, when a new internal refresh request occurs before the refresh operation is performed. For example, the detection signal is output when the interval of access requests is short and no refresh operation can be inserted between the access operations. That is, in the semiconductor memory in which refresh operations are performed automatically, it is possible to evaluate the minimum interval of supplying access requests. As a result, the evaluation time can be reduced with a reduction in the development period of the semiconductor memory.
摘要:
A refresh signal is output in response to a refresh request generated at predetermined cycles, and a refresh operation is performed. The refresh operation ends when a conflict occurs between an access request and the refresh request. Consequently, an access operation corresponding to the access request can be started earlier with a reduction in access time. The access time can be reduced further by changing the end time of the refresh operation in accordance with the timing of supply of the access request. Since a test circuit for notifying the state of the refresh operation to exterior is formed, the operation margin of the refresh operation can be evaluated in a short time. As a result, it is possible to reduce the development period of the semiconductor memory.
摘要:
The present invention is a self-test circuit (BIST) incorporated in the memory device, which is activated in response to a test activation signal from outside. When this self-test circuit is activated in response to a test activation signal (WBIZ) from outside, it generates a test operation command (WBI-CMD), generates a test address (WBI-ADD), and generates test data (WBI-DATA). Furthermore, after the self-test circuit writes the test data to a memory cell, it effects a comparison to establish whether or not the read data that is read from this memory cell is the same as the test data that was written thereto and stores information as to the result of this comparison. This comparison result information is then output to the outside.
摘要:
A semiconductor device which receives addresses in synchronism with a clock signal and receives data in synchronism with a strobe signal includes address-latch circuits, a first control circuit which selects one of the address-latch circuits in sequence in response to the clock signal, and controls the selected one of the address-latch circuits to latch a corresponding one of the addresses in response to the clock signal, and a second control circuit which selects one of the address-latch circuits in sequence in response to the strobe signal, and controls the selected one of the address-latch circuits to output a corresponding one of the addresses in response to the strobe signal.
摘要:
Provided is a memory device in which the decrease of the effective bandwidth caused by the refresh operation of the memory device has been solved, a memory controller of the memory device, and a memory system thereof. A memory device that is operated in response to a command from a memory controller has a plurality of banks that respectively have memory cores including memory cell arrays and decoders and are selected by bank addresses; and a control circuit, which, in response to a background refresh command, causes the memory cores within refresh target banks set by the memory controller to successively execute refresh operation a number of times corresponding to refresh burst length that is set by the memory controller, and, in response to a normal operation command, further causes the memory cores within banks other than the refresh target banks and selected by the bank addresses to execute normal memory operation corresponding to the normal operation command, during the refresh operation executed by the memory cores within the refresh target banks.
摘要:
A refresh signal is output in response to a refresh request generated at predetermined cycles, and a refresh operation is performed. The refresh operation ends when a conflict occurs between an access request and the refresh request. Consequently, an access operation corresponding to the access request can be started earlier with a reduction in access time. The access time can be reduced further by changing the end time of the refresh operation in accordance with the timing of supply of the access request. Since a test circuit for notifying the state of the refresh operation to exterior is formed, the operation margin of the refresh operation can be evaluated in a short time. As a result, it is possible to reduce the development period of the semiconductor memory.
摘要:
An image memory, image memory system, and memory controller that are capable of efficiently accessing a rectangular area of two-dimensionally arrayed data are provided. The memory device has: a memory cell array that has a plurality of memory unit areas, each of which is selected by addresses; a plurality of input/output terminals; and an input/output unit provided between the memory cell array and the plurality of input/output terminals. Each of the memory unit areas stores therein data of a plurality of bytes or bits corresponding to the plurality of input/output terminals respectively, and the memory cell array and the input/output unit access a plurality of bytes or bits stored in a first memory unit area corresponding to the input address and in a second memory unit area adjacent to the first memory unit on the basis of the input address and combination information of the bytes or bits in response to a first operation code, and then, from the plurality of bytes or bits within the accessed first and second memory unit areas, associate a combination of the plurality of bytes or bits based on the combination information, with the plurality of input/output terminals.