An IC card, or Integrated Circuit Card, is a small device embedded with a microchip and housed in a plastic card. It was first introduced in the early 1970s and developed by the French company BULL in 1976. Since then, it has been widely used in various sectors such as finance, transportation, healthcare, identity verification, and catering. The IC card offers numerous advantages, including resistance to water, moisture, and magnetic interference, along with high security, long lifespan, and anti-counterfeiting features.

In China, the development of economic information systems has led to initiatives like the "Golden Bridge," "Golden Card," and "Golden Gate" projects. Among these, the "Golden Card" project, focused on electronic money, plays a vital role in advancing the country's digital economy. This initiative uses either magnetic cards or IC cards as data carriers, leveraging existing networks from the Ministry of Posts and Telecommunications and the People's Bank of China. Through the "Golden Bridge" network, it creates an efficient economic information system that supports banking, commerce, and tourism. Due to its reliability and security, the IC card became the preferred choice for this project.

IC cards can be categorized based on the type of integrated circuit they contain. These include memory cards, which use E2 PROM technology; logical encryption cards, which incorporate encryption logic and E2 PROM; and CPU cards, which feature a central processing unit (CPU), RAM, ROM, and an on-chip operating system (COS). In terms of data transmission, IC cards are also divided into contact and non-contact types. Contact-based cards are currently more widely used due to their reliability and compatibility with existing systems.

When developing an IC card reader/writer, the AT24C01 memory card from ATMEL was chosen. This card has a capacity of 1K bits (128 × 8), supports up to 100,000 write cycles, and maintains data integrity for over 100 years. The module complies with the ISO/IEC 7816 standard, and its contact layout is detailed in Table 1-38 and Figure 1-123.

The hardware design of the IC card reader/writer includes a basic single-chip system, a display and keyboard interface, and an IC card interface. The core component is the 8031 microcontroller, supported by 2764 ROM, 6264 RAM, and 74LS373 for address latching. The display and keyboard are managed by the 8279 chip, which simplifies programming and reduces the load on the main processor.

The IC card interface consists of a bidirectional analog switch and pull-up resistors, ensuring compatibility with the unique electrical characteristics of the IC card. Proper hardware design is crucial to prevent damage and ensure reliable operation. If not designed correctly, the IC card may suffer from premature failure or even burnout.

During the insertion and removal of contact-type IC cards, there is a risk of unstable contact, which can lead to power surges or signal disruptions. To prevent this, the reader/writer design incorporates an interrupt-based mechanism. Switch signals are processed through AND and NOT gates and connected to external interrupts of the 8031, allowing immediate response to card insertion or removal events.

To further enhance protection, the CD4066 bidirectional analog switch is used to control the connection between the IC card and the reader/writer. This ensures that all signal and power lines are disconnected when the card is removed, reducing the risk of damage. Additionally, separate power supplies are used for the IC card and the host system. The IC card is powered by an LM317 voltage regulator, while the host uses a 7805, minimizing power-related interference and improving overall reliability.

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