Other

Hitachi, Ltd.

Tomoya Takasuga

Takaaki Suzuki

Atsushi Hasegawa

Norio Nakagawa

A combination mode a data transfer for a transfer source and a transfer destination is previously defined by a value of resource select information of a control register (CHCRn). An address comparator circuit (SACn, DACn) has judging logic specified by the defined contents and detects, depending on its logical structure, a data transfer address error in the a data transfer controller ( ) on the basis of such logical structure, in accordance with resource select information and the transfer source address and transfer destination address of the address registers (SARn, DARn). Since the data transfer is started only when the resource select information matches with the setting information of both address registers, high reliability can be assured for memory protection in the data transfer operation by the data transfer controller.

Data transfer controller, microcomputer and data processing system

An input/output device used as a transfer request source outputs a data transfer set command for specifying each transfer channel, each transfer address, the number of transfers, etc. onto a bus together with a data transfer request without being involving use of the CPU. According to the data transfer set command, data transfer control information is set to direct memory access control means, and DMA transfer is started between the input/output device and a memory designated by the transfer address, for example. When the input/output device used as a data transfer request source desires to perform data transfer without regard to a state of processing by the microcomputer, it can perform data transfer processing with its own timing and the data transfer with the input/output device as a principal base is allowed.

Data processing system and microcomputer

An input/output device used as a transfer request source outputs a data transfer set command for specifying each transfer channel, each transfer address, the number of transfers, etc. onto a bus together with a data transfer request without involving the use of the CPU. According to the data transfer set command, data transfer control information is set to direct memory access control means, and DMA transfer is started between the input/output device and a memory designated by the transfer address, for example. When the input/output device used as a data transfer request source desires to perform data transfer without regard to the state of processing by the microcomputer, it can perform data transfer processing with its own timing and the data transfer with the input/output device as a principal base is allowed.

A combination mode a data transfer for a transfer source and a transfer destination is previously defined by a value of resource select information of a control register (CHCRn). An address comparator circuit (SACn, DACn) has judging logic specified by the defined contents and detects, depending on its logical structure, a data transfer address error in the data transfer controller (,) on the basis of such logical structure, in accordance with resource select information and the transfer source address and transfer destination address of the address registers (SARn, DARn). Since the data transfer is started only when the resource select information matches with the setting information of both address registers, high reliability can be assured for memory protection in the data transfer operation by the data transfer controller.

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Kodaira, Japan

Tomoya Takasuga