Interface circuit between intelligent temperature sensor TCN75 with two-wire serial interface and 89C51 single-chip microcomputer

The interface circuit between TCN75 and 89C51 microcontroller is shown in the figure. Connect the address input terminals A2~A0 of TCN75 to high level UDD, and set the address code to 111. 89C51 implements the chip selection function through software. The serial data receiving terminal (RXD) and serial data transmitting terminal (TXD) of 89C51 are connected to the SDA and SCL terminals of TCN75 in turn. The interrupt/compare signal of TCN75 is connected to the interrupt terminal INT0 of 89C51.