Patent ID: 7212599
Filing Date: 2007-05-01
Classification: G06F,H04J

Abstract:
1. An apparatus for receiving input data and a write enable signal at a non-uniform first write data rate and for providing output data at a substantially uniform second read data rate, the apparatus comprising: a saturating elastic store having a plurality of data storage locations, the saturating elastic store receiving the input data and the write enable signal, the saturating elastic store operative to store input data concurrent with the write enable signal at one of said plurality of data storage locations, the saturating elastic store further operative to provide a data storage level signal indicative of the number of data storage locations currently used; a digital filter having a transfer function coupled to the saturating elastic store and receiving said data storage level signal, said digital filter operative to filter said data storage level and to provide the filtered data storage level signal as an output control word; and a digitally controlled read enable generator providing a read enable signal at the second read data rate, the digitally controlled read enable generator coupled to the digital filter and receiving as an input said control word from said digital filter, said digitally controlled read enable generator responsive to said control word by varying said read enable signal from said second read data rate, said digitally controlled read enable generator further coupled to the saturating elastic store and providing the read enable signal to the saturating elastic store, wherein said saturating elastic store is further operative to read data stored at one of said plurality of storage locations and to provide said read data as an output concurrently with said read enable signal, and wherein at least one of said saturating elastic store and said digitally controlled read enable generator is further operative: in the event substantially all of said plurality of data storage locations within said saturating elastic store are currently being used, to vary at least one of said write data rate and said read data rate to prevent an overflow condition of said saturating elastic store; and in the event substantially none of said plurality of data storage locations within said saturating elastic store is currently being used, to vary at least one of said write data rate and said read data rate to prevent an underflow condition of said saturating elastic store, wherein the digitally controlled read enable generator includes; a stuff enable generator for providing a stuff enable signal, the stuff enable generator coupled to the digital filter and receiving the control word therefrom; a read enable signal generator for providing read enable signals at the second data rate, the read enable signals including data stuff opportunities interspersed between the read enable signals, the data stuff opportunities allowing for the adjustment of the nominal read data rate by providing an opportunity for an additional read enable signal during a corresponding stuff opportunity, the read enable signal generator also providing the stuff opportunities to the stuff signal generator; the stuff enable generator providing a stuff enable signal to the read enable generator as a function of the control word and the corresponding stuff opportunity, wherein the read enable signal generator is responsive to the stuff enable signal by providing an additional read enable signal at the corresponding stuff opportunity, and wherein the stuff enable generator includes: