Computer interface system

Abstract From the Canadian patent

A data transfer interface unit for use with a computer having a parallel data port to transfer data between the computer and one or more peripheral units. The interface unit generates handshaking signals when the start of communication with a peripheral unit is initiated and temporarily stores blocks of data to be transferred between the computer and the peripheral unit. The interface generates an interface clock signal which is synchronous with the computer's clock signal and begins the transfer of the data after a predetermined time delay from the time at which the start has been initiated the time delay being, an integral multiple of the interface clock period and the data transfer being …