Microcomputer with built-in serial input-output circuit and collision detection circuit responsive to common input-output line being occupied

摘要

Even in the case where a microcomputer according to the present invention is directly connected to a bus in a LAN, it is possible to upgrade the data transfer speed of the LAN. When a built-in exclusive-OR circuit in the SIO of the microcomputer detects the discordance between a signal at an RxD terminal and a signal at a TxD terminal, a D flip-flop circuit generates and sends out an interrupt signal to the CPU. The CPU is made to recognize the collision of signals by the generation of the interrupt signal.