| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a data switching device capable of fairly selecting plural input ports with a simple circuit. SOLUTION: This data switching device is provided with an up counter 1, a down counter 2, a counter selector circuit 3 for selecting either a value measured by the up counter 1 or value measured by the down counter 2, a port selector circuit 4 for selecting any one of plural input ports Lin on the basis of the output of the counter selector circuit 3 and a buffer 5 for storing a packet sent from the input ports Lin selected by the port selector circuit 4. The port selector circuit 4 switches whether the fetch priority of the input ports Lin1-Lin4 is to be changed in ascending order or descending order by alternately selecting the up counter 1 and the down counter 2 each time a packet is fetched. Thus, the respective input ports Lin1-Lin4 can be equally selected.</p> |
