Chapter Memory Partitions | Intel Microcontroller, 80C196NU guide

CHAPTER 5 MEMORY PARTITIONS

This chapter describes the organization of the address space, its major partitions, and the 1-Mbyte and 64-Kbyte operating modes. 1-Mbyterefers to the address space defined by the 20 external address lines. In 1-Mbyte mode, code can execute from almost anywhere in the 1-Mbyte space. In 64-Kbyte mode, code can execute only from the 64-Kbyte area FF0000–FFFFFFH. The 64- Kbyte mode provides compatibility with software written for previous 16-bit MCS® 96 micro- controllers. In either mode, nearly all of the 1-Mbyte address space is available for data storage.

Other topics covered in this chapter include the following:

•the relationship between the 1-Mbyte address space defined by the 20 external address lines and the 16-Mbyte address space defined by the 24 internal address lines

•extended and nonextended data accesses

•a windowing technique for accessing the upper register file and peripheral special-function registers (SFRs) with direct addressing

•examples of external memory configurations for the 1-Mbyte and 64-Kbyte operating modes

•a method for remapping the 4-Kbyte internal ROM (83C196NP only)

5.1MEMORY MAP OVERVIEW

The instructions can address 16 Mbytes of memory. However, only 20 of the 24 address lines are implemented by external pins: A19:0 in demultiplexed mode, or A19:16 and AD15:0 in multi- plexed mode. The lower 16 address/data lines, AD15:0, are the same as those in all other MCS 96 microcontrollers. The four extended address lines, A19:16, are provided by the EPORT. If, for example, an internal 24-bit address is FF2018H, the 20 external-address pins output F2018H. Further, the address seen by an external device depends on how many of the extended address lines are connected to the device. (See “Internal and External Addresses” on page 13-1.)

The 20 external-address pins can address 1 Mbyte of external memory. For purposes of discussion only, it is convenient to view this 1-Mbyte address space as sixteen 64-Kbyte pages, numbered 00H–0FH (see Figure 5-1 on page 5-2). The lower 16 address lines enable the device to address page 00H. The four extended address lines enable the device to address the remaining external address space, pages 01H–0FH.

5-1

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.

Intel Microcontroller, 80C196NU, 8XC196NP manual Chapter Memory Partitions, Memory MAP Overview

Models: Microcontroller 80C196NU 8XC196NP

CHAPTER 5

MEMORY PARTITIONS

5.1MEMORY MAP OVERVIEW

Microcontroller, 80C196NU, 8XC196NP specifications