摘要:
A system integrated circuit that identifies the cause of a malfunction even if the number of output terminals of a system LSI to be assigned to internal buses in the system LSI is strictly restricted. Comparators 11 to 15 are connected to any of a plurality of buses. Each comparator judges whether a certain expected value matches data transferred on a bus connected to the comparator. The selector unit 10 selects one of the plurality of buses in accordance with the judgement result of the comparator, and outputs data transferred on the selected bus to outside the system integrated circuit so that an observer can observe internal state of the system integrated circuit from outside.
摘要:
The remote control signal reception controller receives control data transmitted from a remote control signal sender. The remote control signal reception controller informs a CPU that controls a device of the information on the received control data by interrupting the CPU. When doing so, the remote control signal reception controller judges whether a piece of control data that has just been received and a preceding piece of control data were consecutively transmitted, and whether these two pieces of control data are the same control data. The remote control signal reception controller interrupts the CPU only once when finding that the same control data is continuously transmitted as the result of this judgement.
摘要:
An apparatus and method for controlling data read access to memory, in response to an access request sent through a system bus. The apparatus includes an data storage device for preserving data corresponding to a predetermined address; a judging device for judging whether an access address indicated by the access request matches the predetermined address; and a control device for making the data storage device output data preserved therein to the system bus when the access address has been judged to match the predetermined address, and for making the data storage device hold data corresponding to a next address subsequent to the access address when the access address has been judged not to match the predetermined address.
摘要:
A cross-bus switch apparatus which establishes simultaneously two or more pairs of connections between (i) a source bus arbitrarily selected from a plurality of source buses connected to one or more source apparatuses and (ii) a destination bus arbitrarily selected from a plurality of destination buses connected to one or more destination apparatuses. The cross-bus switch apparatus includes: a plurality of cross-bus switch units. The plurality of source buses are grouped into a plurality of source bus groups which are each connected to one of the plurality of cross-bus switch units. The plurality of destination buses are grouped into a plurality of destination bus groups which are each connected to one of the plurality of cross-bus switch units. Each cross-bus switch unit is connected to either (i) a source bus group or a destination bus group, or (ii) a source bus group and a destination bus group.
摘要:
A DMA control device and a data transfer method, which make it possible to use a DMA channel independent of an operation mode of a processor and realize the protection of DMA control parameters during DMA operation (during a data transfer), while reducing the number of shift of an operating mode of the processor as small as possible, are provided. In requesting a DMA start by locking an access to a ch-0 DMA control register 114 in a secure mode, a CPU 101 instructs an unlock set register 118 to release an access lock when the transfer is completed. Then, when a parameter controlling circuit 119 receives a notification of transfer completion from a ch-0 state managing circuit 116, such parameter controlling circuit instructs a lock set register 115 to release the lock in accordance with the setting of the unlock set register 118.
摘要:
A master device in a system including a bidirectional bus and at least one device manages whether the system is in an access state in which the master device permits an access to or from one device or a non-access state in which the master device permits an access to none of the devices. The master device drives the bidirectional bus using a predetermined current to transfer data to or from one device connected to the bidirectional bus when the system is in the access state. When the state of the system changes from the access state to the non-access state, the master device drives the bidirectional bus in order to stabilize the potential of the bidirectional bus to keep the bus potential from changing when the system is in a non-access state, thereby eliminating the need for conventional pull-up/pull-down resistors for stabilizing the bus potential during a non-access state.
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:
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.