CHAPTER 7 CAN SERIAL COMMUNICATIONS CONTROLLER

The 87C196CB has a peripheral not found in the 8XC196NT — the CAN (controller area net- work) peripheral. The CAN serial communications controller manages communications between multiple network nodes. This integrated peripheral is similar to Intel’s standalone 82527 CAN serial communications controller. It supports both the standard and the extended message frames specified by CAN 2.0 protocol parts A and B developed by Robert Bosch, GmbH. This chapter describes the integrated CAN controller and explains how to configure it. Consult Appendix A, “Signal Descriptions,” for detailed descriptions of the signals discussed in this chapter.

7.1CAN FUNCTIONAL OVERVIEW

The integrated CAN controller transfers messages between network nodes according to the CAN protocol. The CAN protocol uses a multiple-master, contention-based bus configuration, which is also called CSMA/CR (carrier sense, multiple access, with collision resolution). Each CAN controller’s input and output pins are connected to a two-line CAN bus through which all com- munication takes place (Figure 7-1).

ABS

 

 

 

 

 

 

 

 

 

RXCAN

 

CAN_L

 

 

 

Dashboard

 

196Cx

 

Bus

 

 

 

Rx0

 

TXCAN

CAN_H

CAN_L

 

 

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device

Driver

 

Bus

 

82527

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CAN_H

Tx0

 

 

 

 

Driver

 

 

 

 

 

 

Engine

 

 

 

 

 

 

 

 

 

RXCAN

 

CAN_L

 

 

Security System

 

196Cx

 

 

 

 

 

 

 

Bus

 

CAN_L

 

Rx0

 

Bus

 

 

 

 

 

device

TXCAN

Driver CAN_H

 

 

 

Bus

 

 

 

 

 

 

 

CAN_H

Tx0

82527

CPU

 

 

 

 

Driver

 

 

 

 

 

 

Transmission

 

 

 

Bus

 

 

 

 

196Cx

RXCAN

 

CAN_L

 

 

 

 

 

Bus

 

CAN

 

 

 

 

device

 

 

 

 

 

 

TXCAN

Driver CAN_H

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

A2588-02

Figure 7-1. A System Using CAN Controllers

7-1

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Intel 87C196CB, 8XC196NT user manual Can Serial Communications Controller, Can Functional Overview

8XC196NT, 87C196CB specifications

The Intel 87C196CB and 8XC196NT are microcontrollers from the C196 family, which was designed to meet the demands of embedded control technology. These microcontrollers are popular in various applications due to their robust architecture, extensive I/O capabilities, and specialized functionality, making them ideal for automotive, industrial, and communication systems.

The 87C196CB is distinguished by its 16-bit architecture, offering a balance of processing power and efficiency. It features a 16-bit data bus, which allows for fast data processing, and a 16-bit address bus, supporting up to 64KB of program memory. The microcontroller integrates on-chip memory, including 2KB of ROM and 128 bytes of RAM, which facilitates faster execution of programs and data handling.

One of the standout features of the 87C196CB is its versatility in I/O operations. It comes equipped with 32 general-purpose I/O lines that can be configured for various functions, including input, output, and interrupt handling. This flexibility enables developers to optimize the microcontroller for their specific application needs.

The 8XC196NT builds on the capabilities of its predecessor, offering advanced functionalities such as an enhanced instruction set and integrated peripherals. It includes additional features like timers, serial communication interfaces, and analog-to-digital converters, which expand its usability in complex embedded systems. The 8XC196NT supports multiple addressing modes, allowing for more efficient programming and memory management.

Both microcontrollers utilize innovative technologies that improve performance and power efficiency. The on-chip operating system support aids in real-time processing and multitasking, making them suitable for time-sensitive applications. Power management features are also incorporated, allowing these microcontrollers to operate in low-power modes, which is crucial for battery-operated devices.

The 87C196CB and 8XC196NT microcontrollers are characterized by their reliability and long service life, meeting the stringent demands of industrial applications. Their ability to perform tasks rapidly, combined with their diverse peripheral support, makes them popular choices among engineers and developers designing embedded systems. Overall, the Intel 87C196CB and 8XC196NT microcontrollers remain relevant in the rapidly evolving landscape of embedded technology, facilitating innovative solutions across various industries.