Abstract: Access control is achieved in consideration of write training. Masters issue access requests including a read request and a write request. A memory controller accesses memory in response to the access requests issued by the maters. A central bus-control system controls the output of the access requests issued by the masters to the memory controller. A training circuit conducts training on the memory while the access to the memory is stopped. The central bus-control system further controls the execution of the training on the memory. During the training, the central bus-control system suppresses the output of the read request to the memory controller from among the access requests issued by the masters.

Abstract: When a plurality of write data is merged to generate a code for protecting data stored in the main memory, the write data is protected in the memory controller. A first code generation unit generates a first code based on the write data stored in a first sub memory, and stores the generated first code in a second sub memory. The sub memory controller reads the write data to be merged from the first sub memory, and verifies whether the read write data includes an error by using the first code stored in the second sub memory. When the read write data does not include an error, the sub memory controller merges valid data of the write data read from the first sub memory, and outputs the merged data to a second code generation unit. The second code generation unit generates a second code based on the merged data.

Abstract: Each master issues an access request including a read request and a write request to a memory. A cache caches the write request issued by the master. A central bus control system performs access control for the read request issued by each master and the write request output by the cache. A central bus control system performs access control for the write request issued by each master. The central bus control system performs access control in accordance with a free situation of a buffer of a memory controller. The central bus control system performs access control in accordance with a free situation of the cache.

Abstract: Access control is achieved in consideration of write training. Masters issue access requests including a read request and a write request. A memory controller accesses memory in response to the access requests issued by the maters. A central bus-control system controls the output of the access requests issued by the masters to the memory controller. A training circuit conducts training on the memory while the access to the memory is stopped. The central bus-control system further controls the execution of the training on the memory. During the training, the central bus-control system suppresses the output of the read request to the memory controller from among the access requests issued by the masters.

Abstract: Access control is achieved in consideration of write training. Masters issue access requests including a read request and a write request. A memory controller accesses memory in response to the access requests issued by the maters. A central bus-control system controls the output of the access requests issued by the masters to the memory controller. A training circuit conducts training on the memory while the access to the memory is stopped. The central bus-control system further controls the execution of the training on the memory. During the training, the central bus-control system suppresses the output of the read request to the memory controller from among the access requests issued by the masters.

Abstract: When a plurality of write data is merged to generate a code for protecting data stored in the main memory, the write data is protected in the memory controller. A first code generation unit generates a first code based on the write data stored in a first sub memory, and stores the generated first code in a second sub memory. The sub memory controller reads the write data to be merged from the first sub memory, and verifies whether the read write data includes an error by using the first code stored in the second sub memory. When the read write data does not include an error, the sub memory controller merges valid data of the write data read from the first sub memory, and outputs the merged data to a second code generation unit. The second code generation unit generates a second code based on the merged data.

Abstract: Each master issues an access request including a read request and a write request to a memory. A cache caches the write request issued by the master. A central bus control system performs access control for the read request issued by each master and the write request output by the cache. A central bus control system performs access control for the write request issued by each master. The central bus control system performs access control in accordance with a free situation of a buffer of a memory controller. The central bus control system performs access control in accordance with a free situation of the cache.

Abstract: Access control is achieved in consideration of write training. Masters issue access requests including a read request and a write request. A memory controller accesses memory in response to the access requests issued by the maters. A central bus-control system controls the output of the access requests issued by the masters to the memory controller. A training circuit conducts training on the memory while the access to the memory is stopped. The central bus-control system further controls the execution of the training on the memory. During the training, the central bus-control system suppresses the output of the read request to the memory controller from among the access requests issued by the masters.

Abstract: Provided is a memory control technique for avoiding that the issue of a refresh command and the issue of a calibration command are arranged in succession. The memory control circuit issues a refresh command to make a request for a refresh operation based on a set refresh cycle, and issues a calibration command to make a request for a calibrating operation based on a set calibration cycle, for which the control function of suppressing the issue of the calibration command only for a given time after the issue of the refresh command, and suppressing the issue of the refresh command only for a given time after the issue of the calibration command is adopted.

Abstract: Provided is a memory control technique for avoiding that the issue of a refresh command and the issue of a calibration command are arranged in succession. The memory control circuit issues a refresh command to make a request for a refresh operation based on a set refresh cycle, and issues a calibration command to make a request for a calibrating operation based on a set calibration cycle, for which the control function of suppressing the issue of the calibration command only for a given time after the issue of the refresh command, and suppressing the issue of the refresh command only for a given time after the issue of the calibration command is adopted.

Abstract: Provided is a memory control technique for avoiding that the issue of a refresh command and the issue of a calibration command are arranged in succession. The memory control circuit issues a refresh command to make a request for a refresh operation based on a set refresh cycle, and issues a calibration command to make a request for a calibrating operation based on a set calibration cycle, for which the control function of suppressing the issue of the calibration command only for a given time after the issue of the refresh command, and suppressing the issue of the refresh command only for a given time after the issue of the calibration command is adopted.

Abstract: Provided is a memory control technique for avoiding that the issue of a refresh command and the issue of a calibration command are arranged in succession. The memory control circuit issues a refresh command to make a request for a refresh operation based on a set refresh cycle, and issues a calibration command to make a request for a calibrating operation based on a set calibration cycle, for which the control function of suppressing the issue of the calibration command only for a given time after the issue of the refresh command, and suppressing the issue of the refresh command only for a given time after the issue of the calibration command is adopted.

Abstract: Provided is a memory control technique for avoiding that the issue of a refresh command and the issue of a calibration command are arranged in succession. The memory control circuit issues a refresh command to make a request for a refresh operation based on a set refresh cycle, and issues a calibration command to make a request for a calibrating operation based on a set calibration cycle, for which the control function of suppressing the issue of the calibration command only for a given time after the issue of the refresh command, and suppressing the issue of the refresh command only for a given time after the issue of the calibration command is adopted.