Human–Machine Interface Design of Metal Detector Based on SPI

According to the problem of the human–machine interface design from metal detector, human machine interface display system of metal detector has been designed in this paper, which uses SPI communication protocol as the core. Point of this paper is the study of the communication protocol SPI between metal locator DSP and MCU. Hardware circuit and software design of the human machine interface system have been studied. In the existence of mineral, the system circuit is verified. The experiment indicates that the MCU can accurately read data which are sent from DSP by SPI protocol, meanwhile turn the data into Chinese characters, thus displaying them on the LCD screen when the DSP is running at high speed; besides, it is also proved that the system can not only detect percent of metal in the mineral, the accurateness and the anti-interference performance is also high, the result reach the expected goals.