JPH0398144A - Data transfer device - Google Patents

Abstract

PURPOSE:To improve the data transfer efficiency by selecting another channel device in consideration of the performance and the characteristic of a peripheral device connected to the channel device and deciding intentionally the data transfer direction when a selected channel device has no request for transfer of data and another channel device request the transfer of data. CONSTITUTION:A constitution information storage means 16 stores the constitution information on the channel devices 20 - 23 connected to a data transfer device. A first selection means 13 selects periodically the devices 20 - 23 to transfer data. A 2nd selection means 12 gives the priority to the channel devices which are not selected by the means 13 and have the data transfer requests based on the constitution information and selects these channel devices if the channel devices have no data transfer request via the means 13. Then a means 10 transfers the data in the direction desired by the channel device selected by the means 13 or 12. As a result, the data transfer efficiency is improved.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a data transfer device.

[Conventional technology]

A conventional data transfer device periodically selects a channel device to transfer data in order of channel device number regardless of whether or not it is transferring data, and if the selected channel device does not request data transfer, the selected channel device is selected. Channels that have not been
Even though the C device requested data transfer, no data transfer occurred between the data transfer device and the channel device.

In addition, data transfer has a pair of directions from the data transfer device to the channel device and from the channel device to the data transfer device, and the directions are set periodically, so if data transfer is only in one direction, The bidirectional data transfer path between the data transfer device and the channel device was sometimes not used.

[Problem to be solved by the invention]

In the conventional data transfer device described above, when the selected channel device is not requesting data transfer and another channel device is requesting data transfer, channel device selection control is performed by selecting the data transfer device and the channel. The first problem is that there is a period when the data transfer path between devices is not used, and in the above case, when data transfer requests are received from multiple other channel devices, the characteristics of the peripheral control device connected to the channel device (For example, the data transfer with the peripheral device connected to the peripheral control device can be made to wait.) and the second problem is that the selection of the channel device is not done taking into account the relationship between the data transfer rate and the operating speed of the peripheral device. Problems and data transfer is a pair of directions from the data transfer device to the channel device and from the channel device to the data transfer device, and the directions are set periodically, so data transfer can only occur in one direction. The third problem is that there is a period when the bidirectional data transfer path between the data transfer device and the channel device is not used. [Means for Solving the Problems] The device of the present invention is a data transfer device that shares a bidirectional data transfer path with a plurality of channel devices and controls the plurality of channel devices in a time-sharing manner. configuration information storage means for storing configuration information of the plurality of channel devices connected to the transfer device; first selection means for periodically selecting a channel device to perform data transfer from among the plurality of channel devices; If the first selection means determines that the channel device is not requesting data transfer, giving a priority using the configuration information from among those not selected by the first selection means and requesting data transfer; and a means for transferring data in the direction requested by the channel device selected by the first selecting means or the second;z selecting means. [Example] Next, the present invention will be described with reference to the drawings.

Figure 1 shows an embodiment of the present invention. If data transfer is possible in the next clock cycle, channel devices 20, 21, 22, and 23 each notify the request reception register 11 that data transfer is possible via signal lines 201, 211, 221, and 231. The corresponding bit of request reception register l1 is set to “
1” and data transfer direction register 1.
Set the direction of data transfer in the corresponding bit of 5.
The channel device number register 13 is a register that is unconditionally incremented by 7 regardless of whether data is transferred or not, and holds the channel device number to which data is transferred. The channel device number register 13 sends the channel device number to the adder circuit 14 via the signal line 131, and the adder circuit l4 sends the channel device number to the signal line 14.
1 to the channel device number register 13.

In the next clock cycle, if the bit of the request acceptance register 11 indicated by the channel device number of the channel device number register 13 is set to “1”, the priority control circuit 12 controls the channel device indicated by the channel device number register 13. Data is transferred in the direction indicated by the data transfer direction register 15. If the bit of the request reception register 11 corresponding to the channel device number of the channel device number register 13 is "0", the quest reception register 11 is checked to see if another channel device is requesting data transfer. If another channel device requests data transfer, priority is given to select the channel device to perform the data transfer based on the configuration information of the channel device.

The ellipse information here refers to information such as the transfer performance of a peripheral device connected to a channel device and the presence or absence of an influence between data transfer and operation of the peripheral device. For example, the priority order is set in the elliptical information storage device W16 in order of peripheral devices having the highest transfer speed or in order of being affected by the operation of the peripheral device due to a delay in data transfer.

Based on that information, the priority is set to channel devices 23, 22,
21. If the order of 20 is specified, when the channel device number register 13 indicates the channel device 20, but the channel device 20 has not set "1" to the corresponding bit of the request reception register 11. , the priority order is channel devices 23, 22, and 21.

When the priority control circuit 12 selects a channel device for data transfer, it connects signal lines 212 and 2 to that channel device.
22, 231 to notify the channel device of the selection.

The data buffer 10 has four channel devices 120, 21,
22. This is a buffer that stores data to be transferred to 23 and data transferred from the channel device.The priority control circuit 12 notifies the selected channel device and its data transfer direction via the signal line 121, and starts the data transfer. This is done via the bidirectional bus 101. In this way, even when the channel device indicated by the channel device number register 13 cannot transfer data, data can be transferred with other channel devices, and by appropriately using only the direction in which data is being transferred, both The transfer capacity of the communication bus 101 and the data buffer 10 can be controlled without waste. Furthermore, with recent LSI technology, the amount of hardware that composes the priority control circuit does not pose a serious problem. [Effects of the Invention] As explained above, the present invention provides a method for connecting a selected channel device to another channel device when the selected channel device does not request data transfer and the other channel device requests data transfer. By selecting other channel devices in consideration of the performance and characteristics of peripheral devices, and by intentionally determining the transfer direction in the data transfer state, data transfer can be performed efficiently.

[Brief explanation of drawings]

Figure 1 shows an embodiment of the present invention.

Claims (1)

[Claims] A data transfer device that shares a bidirectional data transfer path with a plurality of channel devices and controls the plurality of channel devices in a time-sharing manner, comprising: configuration information storage means for storing configuration information of a channel device; first selection means for periodically selecting a channel device for data transfer from among the plurality of channel devices; If data transfer is not requested, a second selection means uses the configuration information to give priority and select from among those not selected by the first selection means and requesting data transfer; and means for transferring data in a direction requested by the channel device selected by the first selection means or the second selection means.