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Intel Microcontroller manual Chapter Advanced Math Features, Enhanced Multiplication Instructions

Models: Microcontroller 80C196NU 8XC196NP

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CHAPTER 3

ADVANCED MATH FEATURES

The 80C196NU is the first member of the MCS® 96 microcontroller family to incorporate en- hanced 16-bit multiplication instructions for performing multiply-accumulate operations and a dedicated, 32-bit accumulator register for storing the results of these operations. The accumulator and the enhanced instructions combine to decrease the amount of time required to perform mul- tiply-accumulate operations. The instructions and accumulator support signed and unsigned inte- gers as well as signed fractional data. This chapter describes the 80C196NU’s advanced mathematical features.

3.1ENHANCED MULTIPLICATION INSTRUCTIONS

The 16-bit multiplication instructions, MULU and MUL, that exist for all MCS 96 microcontrol- lers have been enhanced for the 80C196NU. The MULU instruction supports unsigned integers, while the MUL instruction supports signed integers and signed fractionals.

When you execute a 16-bit multiplication instruction with a destination address that is 0FH or below, the 80C196NU automatically stores the result in the accumulator. If bit 3 of the destination address is set (address 08H, 09H, …, 0FH), the 80C196NU clears the accumulator before it stores the result of the current instruction. If bit 3 of the destination address is clear (address 00H, 01H, …, 07H), it adds the result of the current instruction to the existing contents of the accumulator.

This simple example illustrates the results of consecutive multiply-accumulate instructions. The results of the first three instructions are automatically added together in the accumulator, while the last instruction clears the accumulator before the result is stored.

register_1 = 10 decimal (0AH),register_2 = 20 decimal (14H) register_3 = 30 decimal (1EH),register_4 = 40 decimal (28H)

mul 00H,register_1,register_2 ;10×20= 200. Accumulator = 200 decimal. mul 00H,register_3,register_4 ;30×40=1200. Accumulator =1400 decimal. mul 00H,register_2,register_4 ;20×40= 800. Accumulator =2200 decimal. mul 08H,register_2,register_3 ;20×30= 600. Accumulator = 600 decimal.

Table 3-1 compares the instructions required to perform a multiply-accumulate operation for the 8XC196NP and those required for the 80C196NU. The 8XC196NP requires four instructions, while the 80C196NU requires only one to accomplish the same operation. The four 8XC196NP instructions take a total of 32 state times to execute, while the single 80C196NU instruction takes only 16 state times. In addition, the 80C196NU can operate at twice the frequency of the 8XC196NP; therefore, a state time for the 80C196NU is half that of the 8XC196NP. These two factors combine to make the 80C196NU code execute in one-fourth the time required for the 8XC196NP code.

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Intel Microcontroller, 80C196NU, 8XC196NP manual Chapter Advanced Math Features, Enhanced Multiplication Instructions
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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.