The C++ Programming Language: Special Edition

Noise detection apparatus included in a peripheral controller operates to detect automatically when a noise record has been stored in the controller buffer storage unit. The detection apparatus includes control apparatus associated with the buffer storage unit which keeps track of the number of storage locations into which data characters have been stored during a transfer operation. Also included are means for selectively establishing one or more counts corresponding to a minimum number of data characters which must be stored in the buffer storage unit before the controller starts to transfer any data characters to a data processing unit. Each time a minimum number of characters has not been previously stored in the buffer unit when the controller receives a signal indicating the completion of the transfer, the controller clears the buffer storage unit of data characters and continues the transfer.