摘要:
The object of the present invention is to provide a data communication system in which a communication scheme is switched without a decrease in communication efficiency.In a data communication system including first and second devices that are capable of performing full-duplex communication and half-duplex communication via a set of channels connecting the first and second devices, the first device transmits, via the set of channels, to the second device a first communication flag indicating whether half-duplex communication is to be specified in accordance with a communication processing capability of the first device, the second device transmits, via the set of channels, to the first device a second communication flag indicating whether half-duplex communication is to be specified in accordance with a communication processing capability of the second device, and the first and second devices select either a full-duplex communication scheme or a half-duplex communication scheme depending on the first and second communication flags in compliance with a procedure predetermined between the devices and perform data communication in the selected communication scheme, the selected communication scheme conforming to the communication processing capability of each device.
摘要:
A memory device with a nonvolatile memory and RAM for accessing the nonvolatile memory is generally provided with a table to convert a logical address to a physical address, however, in the invention, the table is divided to a first table on RAM and a second table on the nonvolatile memory. The first table converts specific bits of the logical address to a first physical address indicating a location of the second table. The second table converts the other bits of the logical address to a physical address of a representative page of pages contained in a storage area corresponding to the logical address. A unit operable to access data (a writing unit operable to, a reading unit operable to, and an erasing unit operable to) reaches a target physical address based on the logical address. Such configuration can reduce the capacity of each conversion table.
摘要:
A memory device that is free from problems resulted from the characteristics of nonvolatile memory chips. The problems are specifically those occurring at the time of data transfer between nonvolatile memory chips, e.g., data error or program error occurring after data transfer. In the memory device, an error correction code process unit applies error detection to data read from a nonvolatile memory chip to a data line for data transfer. For such detection, an error correction code for the data is referred to. At the time of data transfer between the nonvolatile memory chips, if the data is detected as containing a correctable error, a writing unit writes the corrected data to a nonvolatile memory, which is the transfer destination. In this manner, at the time of data transfer between the nonvolatile memory chips, the error never fails to be detected before data writing.
摘要:
A memory device with a nonvolatile memory and RAM for accessing the nonvolatile memory is generally provided with a table to convert a logical address to a physical address, however, in the invention, the table is divided to a first table on RAM and a second table on the nonvolatile memory. The first table converts specific bits of the logical address to a first physical address indicating a location of the second table. The second table converts the other bits of the logical address to a physical address of a representative page of pages contained in a storage area corresponding to the logical address. A unit operable to access data (a writing unit operable to, a reading unit operable to, and an erasing unit operable to) reaches a target physical address based on the logical address. Such configuration can reduce the capacity of each conversion table.
摘要:
A communication system performs communication while switching between full-duplex communication and half-duplex communication. A slave device, which receives command packet signals requesting to write or read data from the master device, stores information in a response packet signal that specifies half-duplex communication in response to one of the received packet signals, and transmits the response packet signal to the master device, when the number of the received command packet signals has reached the maximum number of the command packet signals storable in a command signal queue.
摘要:
A data communication system for starting transmission and reception of target data for processing upon recognition that switching between communication modes is completed. The data communication system includes a master communication device and a slave communication device that continuously perform, at a time of switching from half-duplex communication to full-duplex communication, (i) a handshake using a directional control code indicating the switching and a preamble code indicating completion of the switching and (ii) a handshake using the preamble code and an acknowledge code indicating receipt of the preamble code, whereby each of the devices recognizes that the switching between communication modes by the opposite device is completed and starts transmission and reception of the target data.
摘要:
An interrupt request cannot be transmitted while a data read command or a data write command transmitted from a host device to a slave device is being processed in a half-duplex mode. Disclosed are a host device and a slave device that are set to a full-duplex mode by temporarily switching the communication direction of a first transmission channel or a second transmission channel after completing transmission and reception of a predetermined number of data packets in the half-duplex mode. The host device or the slave device can thus transmit an interrupt request, such as a request associated with a wait status or a busy status, to its communication target using the temporary full-duplex mode. This enables the host device or the slave device to process such an interrupt request during high-speed data transfer performed in the half-duplex mode.
摘要:
A DMA transfer device transfers data from a first region to a second region in a memory allowing high-speed page access. The DMA transfer device includes: a first detecting unit for detecting a plurality of read areas that form the first region, each read area being located between page boundaries; a second detecting unit for detecting a plurality of write areas that form the second region, each write area being located between page boundaries; and an access unit for performing high-speed page access to each of the read areas and each of the write areas.
摘要:
A processor (10) manages, in an instruction management unit (103) and a data attribute management unit (105), secure attributes indicating whether instruction code and data stored in an instruction cache (102) and a data cache (104) of the processor (10) are confidential information. When the instruction code and the data are confidential information, the processor (10) also manages secure processing identification information for indicating in which secure process the confidential information is to be used. When the operating mode is switched from the secure mode to the normal mode, only the confidential information is disabled by a memory disabling unit (108). This prevents confidential information from being analyzed by the processor in the normal mode.
摘要:
An authentication communication system includes an storage medium having an area for storing digital information and an access device for reading/writing digital information from/into the area. The access device authenticates whether the storage medium is authorized according to a challenge-response authentication protocol in which scrambled access information generated by scrambling the access information which shows the area is used. The storage medium authenticates whether the access device is authorized. When the access device and the storage medium have authenticated each other as authorized devices, the access device reads/writes digital information from/into the area in the storage medium according to the access information separated from the scrambled access information by the access device.