Serial communication circuit and A/D conversion system having the same

摘要

A serial communication circuit for performing full duplex serial communication with a microcomputer includes a counter and a timer. The counter is incremented by each pulse of a serial clock signal output from the microcomputer. When the counter reaches the number of bits of serial data output from the microcomputer, the counter outputs a load signal to a receiving register. The timer starts to count after the counter outputs the receiving load signal for the first time and continues to count during the serial communication. The timer expires at a predetermined time interval. Each time the timer expires, the timer outputs a timer signal. In response to the timer signal, a synchronous signal is output to the microcomputer, the counter is cleared to zero, and data to be output to the microcomputer is loaded into a sending register.