1. Design requirements and objectives
This design is composed of STC89C52 single-chip circuit + RFID module circuit + 1602 liquid crystal display circuit + power supply circuit. There are 3 cards in the system, which represent Zhang San, Li Si, and Wang Er in order. Anyone who swipes the card becomes a function, the 1602 LCD responds and displays "N" if the card is not swiped, and "Y" is displayed after the card is successfully swiped. The second line of the LCD displays the number of swiping cards, that is, the total number of attendance.
2. Design ideas and plans
(1) Control chip selection
Using ST's STC89C52 microcontroller as the main controller, STC89S52 is a low-power, high-performance CMOS 8-bit microcontroller with 8K in-system programmable Flash memory. The single-chip microcomputer has low power consumption, rich interfaces, and low cost, which can fully meet the design requirements.
(2) Display scheme selection
The LCD liquid crystal display is driven by a single-chip microcomputer. It is mainly used to display a large amount of data, text, and graphics. It can display a large number of digits, and the display is clear, diverse and beautiful. At the same time, the programming of the liquid crystal display is simple and cheap, so this solution is adopted .
3. Hardware circuit
