NXP SC16C850IBS: A Comprehensive Technical Overview of the High-Performance UART with 16-Byte FIFOs
The NXP SC16C850IBS stands as a pivotal component in the realm of asynchronous serial communication, representing a significant evolution in Universal Asynchronous Receiver/Transmitter (UART) technology. This device is engineered to facilitate high-speed, reliable data transfer between a microprocessor or microcontroller and serial devices, effectively managing the conversion between parallel and serial data formats. Its architecture is designed to alleviate CPU overhead and enhance system performance through advanced integrated features.
At the core of the SC16C850IBS's performance are its deep 16-byte transmit and receive FIFOs (First-In, First-Out buffers). These buffers are a critical advancement over earlier UARTs with smaller or no FIFOs. By allowing the storage of 16 characters in both transmission and reception pathways, they drastically reduce the number of interrupts presented to the host processor. This enables more efficient data handling, prevents data overrun errors, and is essential for maintaining high data throughput in demanding applications, especially at higher baud rates.
A key feature of this UART is its programmable baud rate generator, capable of operating at speeds up to an impressive 5 Mbps. This flexibility allows the device to interface with a vast array of serial protocols and peripherals operating at different speeds. The baud rate is derived from a reference clock input, which can be divided by a programmable divisor from 1 to (2^16 - 1), offering precise control over communication timing.
The SC16C850IBS supports automatic hardware and software flow control via Request-to-Send (RTS) and Clear-to-Send (CTS) signals. This mechanism is vital for preventing buffer overflows. When the receiver's FIFO is approaching capacity, the UART can automatically de-assert the RTS output, signaling the remote device to pause transmission. Conversely, it monitors the CTS input for commands to halt its own transmission. This hardware-handshaking ensures seamless and error-free data flow without constant CPU intervention.
Modern system integration is simplified through its 3.3V operating voltage and low-power design, making it an ideal choice for power-sensitive and portable applications. Furthermore, it provides a complete modem control interface (including DTR, DSR, DCD, and RI signals), making it suitable for traditional modem connections. The device is offered in a compact and industry-standard HLQFP64 package, optimizing board space.
Internally, the UART is equipped with a fully prioritized interrupt system that directs the CPU's attention to the most critical event, such as receiver line status or data available. For even greater control, it supports a multi-drop mode, often referred to as "9-bit" mode, which is useful for implementing network protocols in multi-processor systems.
ICGOOODFIND Summary: The NXP SC16C850IBS is a high-performance, feature-rich UART that excels in offloading serial communication tasks from the host processor. Its deep 16-byte FIFOs, high-speed 5 Mbps capability, and robust hardware flow control make it an indispensable solution for complex embedded systems, industrial controls, networking equipment, and point-of-sale terminals where reliable, high-throughput serial data transfer is paramount.
Keywords: UART, FIFO, Flow Control, Baud Rate, Serial Communication.
