Data input/output circuit for a digital signal processing system

Abstract

A data input/output circuit includes a 32-bit reversible shift register (1) which includes four 8-bit reversible shift registers (2-5). Input gate circuits (6, 7) selectively apply data being inputted in a bit-serial fashion from an external to the 8-bit reversible shift registers (3, 4), and output gate circuits (8-12) selectively output data being stored in arbitrary stages of the 32-bit reversible shift register (1) in a bit-serial fashion. Input latches (13-15) and output latches (16-18) each of which is an 8-bit latch are connected to the respective 8-bit reversible shift registers (2-4) and a data bus (19). The input latches (13-15) hold the data being stored in the 8-bit reversible shift registers (2-4) and send the same onto the data bus (19) in a bit-parallel fashion, and the output latches (16-18) hold the data being sent from the data bus (19) and preset the same into the 8-bit reversible shift registers (2-4) in a bit-parallel fashion.

Dependencies are inferred from the claim text.