Serial data processor capable of transferring data at a high speed

Abstract

A serial data processor is coupled to a single data line and a single clock line for serial data transfer in synchronism with a clock signal. The data processor comprises a shift register coupled to the serial data line and operated to serially output the data in synchronism with a clock on the clock line, and an output buffer connected to receive the data serially outputted from the shift register and coupled to sequentially output the received data to the data line. This output buffer includes a push-pull driver having an output connected to the data line and an input driven by the data serially outputted from the shift register. A clock counter is coupled to receive the clock on the clock line so as to maintain the push-pull driver in an operable condition until the count value reaches a predetermined value and to bring the output of the push-pull driver into a floating condition after the count value reached a predetermined value. There is provided a data line control circuit coupled to the data line and controlled by the clock counter to bring the data line to a high level after the count value of the clock counter reaches the predetermined value.