Fifo buffer with folded data transmission path permitting selective bypass of storage

Claim 1

A first-in first-out type data storage device for storing input data applied to an input portion thereof from an exterior source in the data storage device in response to a write-in control signal and outputting the stored data from an output portion thereof in response to a read-out control signal, comprising: a data transmission path provided between said input portion and said output portion and having a folded configuration with a going path and a returning path, wherein said going path is connected to said input portion, said returning path is connected to said output portion, and said going and returning paths provide a folded transmission path of a continuous data transmission path; data storage means provided on said going path and said returning path for storing applied data, wherein said going path and said returning path respectively comprise the same number of said data storage means connected in a cascade manner; by passing means for linking said data storage means in said going path and said data storage means in said returning path in one-to-one correspondence to each other; said bypassing means coupling an output portion of said data storage means in said going path to an input portion of the corresponding data storage means in said returning path; valid data detecting means provided corresponding to each of said bypassing means and activated in response to application of the write-in control signal to said data storage means connected to the corresponding bypassing means for detecting the presence and absence of valid data in the corresponding data storage means in said returning path; and transfer control means provided corresponding to each of said bypassing means for activating the corresponding bypassing means in response to a valid data absence detecting signal from the corresponding valid data detecting means, and transferring the input data and the write-in control signal to the corresponding data storage means in said going path through the activated bypassing means for storing the same therein, said transfer control means transferring the input data and write-in control signal to said data storage means in the next stage through said going path in response to a valid data presence detecting signal from the corresponding valid data detecting means.

Claim 12

A method for storing input data applied to an input portion of a first-in first-out type data storage device from an exterior source to the data source device in response to a write-in control signal and outputting the stored data from an output portion of the data storage device in response to a read-out control signal, comprising the steps of: (a) storing applied data in data storage means of a going path and a returning path of a data transmission path provided between the input portion and the output portion of the data storage device, said data transmission path having a folded configuration with said going path connected to the input portion and said returning path connected to the output portion which provide a folded transmission path of a continuous data transmission path; (b) linking the data storage in said going path and said returning path at said step (a) in one-to-one correspondence to each other by coupling an output portion of said data storage means in said going path to an input portion of the corresponding data storage means in said returning path; (c) detecting the presence and absence of valid data in each of said data storage means of said returning path corresponding to said data storage means linked thereto at said step (b) in response to application of the write-control signal; (d) activating the corresponding going path an returning path linked at said step (b) in response to a valid data absence detecting signal from the corresponding detection at said step (c); (e) transferring the input data and the write-in control signal to the corresponding data storage means in said returning path from the corresponding data storage means in said going path linked at said step (b) for storing the same therein; and (f) transferring the input data and the write-in control signal to said data storage means in the next stage through said going path in response to a valid data presence detecting signal from the corresponding detection at said step (c).

Claim 13

A method for storing input data applied to an input portion of a first-in first-out type data storage device from an exterior source to the data source device in response to a write-in control signal and outputting the stored data from an output portion of the data storage device in response to a read-out control signal, comprising the steps of: (a) storing applied data in data storage means of a going path and a returning path of a data transmission path provided between the input portion and the output portion of the data storage device, said data transmission path having a folded configuration with said going path connected to the input portion and said returning path connected to the output portion which provide a folded transmission path of a continuous data transmission path; (b) linking the data storage in said going path and said returning path at said step (a) in one-to-one correspondence to each other by coupling an output portion of said data storage means in said going path to an input portion of the corresponding data storage means in said returning path; (c) detecting the presence and absence of valid data in each of said data storage means of said returning path corresponding to said data storage means linked thereto at said step (b) in response to application of the write-control signal; (d) activating the corresponding going path an returning path linked at said step (b) in response to a valid data absence detecting signal from the corresponding detection at said step (c); (e) transferring the input data and the write-in control signal to the corresponding data storage means in said returning path from the corresponding data storage means in said going path linked at said step (b) for storing the same therein; and (f) transferring the input data and the write-in control signal to said data storage means in the next stage through said going path in response to a valid data presence detecting signal from the corresponding detection at said step (c).