In this paper, a microprocessor will be viewed as a stand-alone, self-contained single-chip microcomputer. For this to apply, it must have a central processing unit (CPU), nonvolatile and program memory, and input and output capabilities. A structure that has these can be programmed in some convenient programming language and can interact with the outside world through the input/output (I/O) ports. But there are other less obvious requirements. Clearly, for a self-contained system, the microprocessor must be relatively simple, reasonably small, and hence limited in most of its features-memory, processing power and speed, addressing range, and of course, the number of I/O devices it can interact with. Unlike computers, the designer must have access to most features of the microprocessor - the bus, memory, registers, and all I/O ports. In short, the microprocessor is a mere component with flexible features that the engineer can configure and program to perform a task or a series of tasks. The limits on these tasks are only two: the objective limitations of the microprocessor and the imagination (or capabilities) of the designer. For the purpose of this discussion, it is narrowed down to 8-bit microprocessors since these are some of the simplest and are commonly used in sensor/actuator systems, and because they are representatives of all microprocessors (16and 32-bit microprocessors are also in common use, but the principles involved in interfacing are essentially the same). Even within these there are a number of architectures being used.

Chapter Contents:

• 12.1 Introduction
• 12.2 The Microprocessor as a General Purpose Controller
• 12.2.1 Architecture
• 12.2.2 Addressing
• 12.2.3 Execution and Speed
• 12.2.4 Instruction Set
• 12.2.5 Input and Output
• 12.2.6 Clock and Timers
• 12.2.7 Registers
• 12.2.8 Memory
• 12.2.9 Power
• 12.2.10 Other Peripherals and Functionalities
• 12.2.11 Programs and Programmability
• 12.3 General Requirements for Interfacing Sensors and Actuators
• 12.3.1 Signal Level
• 12.3.2 Impedance
• 12.3.3 Response and Frequency
• 12.3.4 Input Signal Conditioning
• 12.3.4.1 Offset
• 12.3.4.2 Scaling
• 12.3.4.3 Isolation
• 12.3.4.4 Loading
• 12.3.5 Output Signals
• 12.4 Errors
• 12.4.1 Resolution Errors
• 12.4.2 Computation Errors
• 12.4.3 Sampling and Quantization Errors
• 12.4.4 Conversion Errors
• 12.5 Problems

Inspec keywords: microprocessor chips

Other keywords: registers; 16-bit microprocessors; bus; CPU; central processing unit; actuator systems; sensor systems; input-output ports; 8-bit microprocessors; single-chip microcomputer; programming language; program memory; 32-bit microprocessors

Subjects: Microprocessor chips; Microprocessors and microcomputers