SERIAL I/O (SIO) PORT

The receive interrupt (RI) flag indicates whether an incoming data byte has been received. The transmit interrupt (TI) flag indicates whether a data byte has finished transmitting. These flags also set the corresponding bits in the interrupt pending register. A reception or transmission sets the RI or TI flag in SP_STATUS and the corresponding interrupt pending bit. However, a soft- ware write to the RI or TI flag in SP_STATUS has no effect on the interrupt pending bits and does not cause an interrupt. Similarly, reading SP_STATUS clears the RI and TI flags, but does not clear the corresponding interrupt pending bits. The RI and TI flags in the SP_STATUS and the corresponding interrupt pending bits can be set even if the RI and TI interrupts are masked.

The transmitter empty (TXE) bit is set if SBUF_TX and its buffer are empty and ready to accept up to two bytes. TXE is cleared as soon as a byte is written to SBUF_TX. One byte may be written if TI alone is set. By definition, if TXE has just been set, a transmission has completed and TI is set.

The received parity error (RPE) flag or the received bit 8 (RB8) flag applies for parity enabled or disabled, respectively. If parity is enabled, RPE is set if a parity error is detected. If parity is dis- abled, RB8 is the ninth data bit received in modes 2 and 3.

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Intel Microcontroller, 80C196NU, 8XC196NP manual Serial I/O SIO Port
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Microcontroller, 80C196NU, 8XC196NP specifications

The Intel 8XC196NP and 80C196NU microcontrollers are part of Intel's renowned 16-bit microcontroller series that gained popularity in the 1980s and 1990s for embedded systems applications. Designed for a variety of applications, these microcontrollers are characterized by their robust performance, versatility, and industry-standard architecture.

The 8XC196NP features an enhanced instruction set with over 100 instructions, allowing for efficient code execution. It operates at clock speeds up to 16 MHz, which contributes to improved performance in time-sensitive applications. The microcontroller is equipped with a 16-bit data bus, enabling more efficient data handling compared to its 8-bit predecessors, thus accommodating complex algorithms and large data sets.

In terms of memory architecture, the 8XC196NP supports an addressable memory space of up to 64 KB of program memory and 64 KB of data memory. This configuration provides sufficient space for large applications while ensuring fast data access. The microcontroller includes integrated features such as timers, serial I/O capabilities, and interrupt processing, which enhance its functionality for real-time applications and control mechanisms.

The 80C196NU, on the other hand, is designed for lower power operation, making it suitable for battery-powered devices. This microcontroller maintains similar features to the 8XC196NP while offering advancements that support low-power consumption. The 80C196NU can also function in a range of temperature environments, making it adaptable for industrial applications.

Both the 8XC196NP and 80C196NU support external memory interfacing, allowing designers to expand the system's capability by connecting additional ROM and RAM. This flexibility makes them appealing for developing complex systems, such as motor controls, industrial automation, and consumer electronics.

Another standout feature of these microcontrollers is their built-in debugging capabilities. Intel provided hardware and software tools that enabled developers to test and troubleshoot their applications effectively, reducing the development time and increasing reliability.

Overall, the Intel 8XC196NP and 80C196NU microcontrollers stand out for their dependability, versatility, and performance, contributing significantly to the evolution of embedded system design. Their legacy continues to influence modern microcontroller technology, ensuring their relevance in a wide array of applications today.
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