An IC card, or Integrated Circuit Card, is a small device that contains an embedded microchip within a plastic card-like structure. It was first introduced in the early 1970s and made its debut in 1976 when the French company BULL developed it. Since then, IC cards have been widely used across various sectors such as finance, transportation, healthcare, identity verification, and even food services. Their secure and durable nature has made them a preferred choice for many applications.

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 stands out as a key effort to promote digitalization in the national economy. This initiative utilizes either magnetic cards or IC cards as data carriers and leverages existing telecommunications and banking networks through the "Golden Bridge" system. The goal is to support sectors such as banking, commerce, and tourism by enabling secure and efficient electronic transactions.

IC cards are particularly favored in this project due to their numerous advantages. They are waterproof, moisture-resistant, anti-magnetic, highly secure, and resistant to counterfeiting. Additionally, they have a long lifespan, making them ideal for use in electronic payment systems and other critical applications.

There are several types of IC cards based on the integrated circuits they contain. These include memory cards, which store data using E2PROM technology; logical encryption cards, which feature encryption logic along with E2PROM; and CPU cards, which integrate a central processing unit (CPU), RAM, ROM, and an on-chip operating system (COS). These variations allow for different levels of security and functionality depending on the application.

IC cards can also be classified by their data transmission method: contact-based and contactless. Contact-type IC cards are currently the most commonly used, and they require direct physical contact with the reader to exchange data. Due to their widespread use, the design of IC card readers and writers must account for varying hardware requirements and read/write protocols.

For example, the AT24C01A memory IC card from ATMEL is often used in such systems. It offers 1K bits of storage (128 x 8), supports up to 100,000 write cycles, and has a data retention period of over 100 years. The IC card modules used comply with the ISO/IEC 7816 standard, ensuring compatibility and reliability in communication with the reader.

The hardware design of an IC card reader/writer typically involves a microcontroller, such as the 8031, along with supporting components like ROM, RAM, and peripheral chips. The circuit is divided into three main sections: the basic microcontroller system, the display and keyboard interface, and the IC card interface itself.

The basic system includes the 8031 microcontroller, 8K ROM (2764), 8K RAM (6264), and an address latch (74LS373). The display and keyboard section uses the 8279 chip to simplify programming and reduce the load on the main processor. The IC card interface consists of a bidirectional analog switch and pull-up resistors, designed to meet the specific electrical requirements of the IC card.

Proper hardware design is crucial to ensure the longevity and reliability of the IC card. If not done correctly, the card may suffer damage or reduced lifespan. Therefore, the reader/writer design incorporates multiple protective measures to minimize risks during insertion and removal.

One important consideration is the power supply. If the IC card is powered during plugging or unplugging, it could lead to damage. To prevent this, the interface is designed to cut off power immediately upon detecting a card removal. Additionally, a status switch on the card holder helps detect whether a card is present, allowing the system to respond accordingly.

However, manual operations introduce unpredictability. Sudden removal of the card during a read/write operation can cause errors or damage. To address this, the design uses interrupt-based detection, where changes in the card status trigger immediate power control. This ensures the card is protected at all times.

To further enhance protection, signal and power lines are routed through a CD4066 bidirectional analog switch, controlled by a dedicated pin. This allows the system to disconnect the card’s connections instantly when it is removed, preventing any potential damage.

Finally, to avoid interference between the IC card and the host system, a dual power supply approach is used. The IC card is powered separately via a stable LM317 voltage regulator, while the host uses a 7805 regulator. This isolation minimizes noise and improves the overall reliability of the IC card’s operations.

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