Patent ID: 7430214

Claim:
A data queue control circuit comprising: a plurality of receiving latches configured to receive packets having various number of words from a plurality of interfaces; buffer queues of a number equal to a largest number of words of a received packet, the buffer queues storing separately on a word by word basis the packets received by the receiving latches; packet storage queues of a number equal to the number of the buffer queues, the packet storage queues storing packets read from the buffer queues; a format determining circuit configured to define in advance a plurality of types of writing formats, which are patterns for writing word data of a received packet into said buffer queues, corresponding to availabilities of the buffer queues, the format determining circuit, when a packet is received by one of the plurality of receiving latches, determining dynamically a writing format corresponding to a current availability of the buffer queues; a packet control circuit configured to store separately on a word by word basis the received packets into the buffer queues, in conformity with the writing format determined by the format determining circuit; a format information storage unit configured to store formats determined by the format determining circuit; and a packet reading circuit configured to recognize positions to store the word data based on the formats stored in the format information storage unit, to read the packets from the packet storage queues, wherein an input of said packet control circuit is connected to an output of said receiving latch and said format determining circuit is arranged in said packet control circuit, an input of said buffer queue is connected to an output of said packet control circuit, an input of said packet storage queue is connected to an output of said buffer queue, an input of said packet read circuit is connected to an output of said packet storage queue, and an input of said packet read circuit is connected to an output of said packet storage queue and an output of said format information storage unit.