A cable call interactive conversation system controlled by single chip microcomputer and used by DTMF encoding technology is introduced,and the system principle,interface of MCS-51 single chip computer with MT8880 and address identification circuit of slave-machine are discussed in this paper.
The author develops a MCU controlled IGBT inverter power source for pulsed TIG welding based on P89C51RD2. The design of hardware circuit includes MCU mini-system, the pulse width modulate circuit, drive circuit for IGBT, welding state identifying circuit.
A single audio discriminator circuit is made up with a NE567 phase locking ring. The interference is cleared up by software and the time signal is picked up from the broadcasting information as the interrupt source of the single chip microcomputer to calibrate electronic clocks.
The research and realization of a kind of samrt phone time-recorder are introduced,whose top management chip,one-chip computer AT89S51,can distinguish the different signal sound of the telephone and the decode message of MT8870 through CR6230 distinguishing circuit for received phone signal and sound to achieve the purpose of writing down call message for human-computer interaction controlled by keyboard for users' information inquiry.