Apparatus and method for generating a partial fullness indicator signal in a fifo

Abstract

Techniques for indicating partial fullness levels of a FIFO comprising a plurality of stages using a partial fullness detector, such as a m-out-of-n detector. According to an embodiment, the m-out-of-n detector is coupled to “n” stages of the FIFO and configured to output a partial fullness indicator signal based on the full/empty states of the stages coupled to the m-out-of-n detector. The m-out-of-n detector may be configured to output the partial fullness indicator signal in a first state when “m” stages coupled to the m-out-of-n detector are full, and to output the partial fullness indicator signal in a second state when “m” stages coupled to the m-out-of-n detector are empty. The number of full stages of the FIFO lies in a first range when the m-out-of-n detector outputs the signal in the first state, and in a second range when the m-out-of-n detector outputs the signal in the second state. The bounds for the ranges may be determined based on factors such as the input and output rate characteristics of the FIFO. The m-out-of-n detector may be used to indicate partial fullness levels for various FIFOs including linear flow-through FIFOs, serial-concurrent-serial (SCS) FIFOs, and the like.