Data communication interface integrated circuit with data-echoing and non-echoing communication modes

Claim 1

An integrated circuit communication interface device, comprising: a plurality of first terminals adapted to be connected to separate parallel data lines; a serial data output terminal; a serial data input terminal; an internal parallel data bus; a parallel data buffer, said data buffer connecting said first terminals to the data bus; a transmit buffer, said transmit buffer connecting said serial output terminal to the data bus; a receive buffer, said receive buffer connecting said serial input terminal to the data bus; a logic circuit connected to control said parallel data buffer, said transmit buffer and said receive buffer, said logic circuit including means for controlling said transmit and receive buffers in accordance with each of a plurality of communication modes, said plurality of modes including: i. a first receive mode in which said device receives serial data on said input terminal and transmits said received data via said output terminal; ii. a first transmit mode in which said device transmits serial data via said output terminal, receives on said input terminal an echoed transmission of said transmitted data, and compares said received transmission with said transmitted data; iii. a second receive mode in which said device receives serial data on said input terminal without transmitting said received data via said output terminal; and iv. a second transmit mode in which said device transmits data via said output terminal without receiving an echoed transmission of said transmitted data; and mode selection means, accessible by said logic circuit, for selecting one of said plurality of communication modes, said device operating in accordance with said selected one of said modes.