8251 USART: Advantages and Disadvantages

The 8251 IC (Integrated Circuit) is a universal synchronous/asynchronous receiver-transmitter (USART) chip developed by Intel. It’s commonly used in microcontroller-based projects and communication systems, providing serial communication capability. This allows microcontrollers and other digital systems to communicate with other devices using serial protocols like RS-232.

The figure depicts 8251 IC pin diagram.

It supports both synchronous and asynchronous communication modes, making it versatile for various applications. The chip includes features like baud rate generation, parallel-to-serial and serial-to-parallel conversion, and control registers for configuring communication parameters.

Interfacing the 8251 IC with a microcontroller involves connecting the necessary control signals and data lines between the two devices to enable serial communication.

Advantages of the 8251 USART

Here’s a breakdown of the benefits offered by the 8251 USART:

1. Versatility: The 8251 IC supports both synchronous and asynchronous serial communication modes. This flexibility makes it suitable for a wide range of applications.

2. Integration: It integrates multiple functions required for serial communication, reducing the need for additional components in a system. This simplifies the design and reduces overall board space.

3. Compatibility: The 8251 IC is compatible with various microcontrollers and digital systems, making it easy to incorporate into existing designs.

4. Configurability: It offers flexibility in configuring communication parameters such as baud rate, data format, and parity settings through its control registers. This allows you to tailor the communication to specific requirements.

5. Reliable Performance: The 8251 IC is a mature and widely used chip with a long history of reliable performance in communication systems. Its proven track record makes it a dependable choice.

Disadvantages of the 8251 USART

Despite its advantages, the 8251 USART also has some limitations:

1. Limited Speed: The maximum baud rate supported by the 8251 IC may be insufficient for some high-speed communication applications, especially compared to newer communication protocols and chips. For demanding applications, other options might be more suitable.

2. External Components: While the 8251 IC integrates many functions, additional external components such as crystal oscillators and capacitors may be required for complete operation, increasing system complexity and cost. These external components add to the overall BOM (Bill of Materials).

3. Power Consumption: Depending on the application and configuration, the 8251 IC may consume significant power, especially in continuous communication scenarios, which can be a concern in battery-powered devices. Power efficiency is an important consideration for portable applications.

4. Availability: Being an older chip, the availability of the 8251 IC may become a concern in the future as newer communication technologies replace older ones, potentially leading to sourcing difficulties for replacement parts or new designs. This obsolescence risk is a factor to consider for long-term projects.

5. Size and Packaging: The 8251 IC may come in larger packages compared to more modern communication chips, which can be a limitation in space-constrained designs or when miniaturization is a priority. Smaller, more compact solutions might be preferred in certain applications.

Conclusion

Despite these limitations, the 8251 IC remains a popular choice for many serial communication applications due to its reliability, versatility, and compatibility with existing systems. It’s a solid option, especially when working with legacy systems or projects where its specific features are well-suited.