Patent ID: 7085325

Claim:
A serial interface unit for the transmission and reception of data comprising: a data source ( 20 ) supplying serial output data a single bit at a time; an output driver ( 22 ) having an input ( 1 ) receiving the serial data and an output ( 2 ) supplying a data output line ( 26 ); and a transmit monitor ( 52 ) connected to the output driver ( 22 ), said transmit monitor ( 52 ) comparing data at said input ( 1 ) of said output driver ( 22 ) and data at said output ( 2 ) of said output driver ( 22 ) and generating an error signal when the compared data do not coincide, said transmit monitor ( 52 ) including an exclusive-OR circuit ( 58 ) with a first input connected to said input ( 1 ) of said output driver ( 22 ), a second input connected to said output ( 2 ) of said output driver ( 22 ) and an output, and a D flip-flop ( 62 ) having a D input connected to said output of said exclusive-OR circuit ( 58 ) and an output, said D flip-flop ( 62 ) temporarily storing the output said exclusive-OR circuit ( 58 ).