13
Microprocessors
The microprocessor is the heart of a microcomputer system. In fact, it forms the central processing unit
of any microcomputer and has been rightly referred to as the computer on a chip. This chapter gives
an introduction to microprocessor fundamentals, followed by application-relevant information, such
as salient features, pin configuration, internal architecture, instruction set, etc., of popular brands of
eight-bit, 16-bit, 32-bit and 64-bit microprocessors from international giants like INTEL, MOTOROLA
and ZILOG.
13.1 Introduction to Microprocessors
A microprocessor is a programmable device that accepts binary data from an input device, processes the
data according to the instructions stored in the memory and provides results as output. In other words,
the microprocessor executes the program stored in the memory and transfers data to and from the
outside world through I/O ports. Any microprocessor-based system essentially comprises three parts,
namely the microprocessor, the memory and peripheral I/O devices. The microprocessor is generally
referred to as the heart of the system as it performs all the operations and also controls the rest of
the system. The three parts are interconnected by the data bus, the address bus and the control bus
(Fig. 13.1).
The memory stores the binary instructions and data for the microprocessor. The memory can be
classified as the primary or main memory and secondary memory. Read/write memory (R/WM) and
read only memory (ROM) are examples of primary memory and are used for executing and storing
programs. Magnetic disks and tapes are examples of secondary memory. They are used to store
programs and results after the completion of program execution. Microprocessors do not execute
programs stored in the secondary memory directly. Instead, they are first copied on to the R/W primary
memory.
Digital Electronics: Principles, Devices and Applications Anil K. Maini
© 2007 John Wiley & Sons, Ltd. ISBN: 978-0-470-03214-5
Microprocessors
The microprocessor is the heart of a microcomputer system. In fact, it forms the central processing unit
of any microcomputer and has been rightly referred to as the computer on a chip. This chapter gives
an introduction to microprocessor fundamentals, followed by application-relevant information, such
as salient features, pin configuration, internal architecture, instruction set, etc., of popular brands of
eight-bit, 16-bit, 32-bit and 64-bit microprocessors from international giants like INTEL, MOTOROLA
and ZILOG.
13.1 Introduction to Microprocessors
A microprocessor is a programmable device that accepts binary data from an input device, processes the
data according to the instructions stored in the memory and provides results as output. In other words,
the microprocessor executes the program stored in the memory and transfers data to and from the
outside world through I/O ports. Any microprocessor-based system essentially comprises three parts,
namely the microprocessor, the memory and peripheral I/O devices. The microprocessor is generally
referred to as the heart of the system as it performs all the operations and also controls the rest of
the system. The three parts are interconnected by the data bus, the address bus and the control bus
(Fig. 13.1).
The memory stores the binary instructions and data for the microprocessor. The memory can be
classified as the primary or main memory and secondary memory. Read/write memory (R/WM) and
read only memory (ROM) are examples of primary memory and are used for executing and storing
programs. Magnetic disks and tapes are examples of secondary memory. They are used to store
programs and results after the completion of program execution. Microprocessors do not execute
programs stored in the secondary memory directly. Instead, they are first copied on to the R/W primary
memory.
Digital Electronics: Principles, Devices and Applications Anil K. Maini
© 2007 John Wiley & Sons, Ltd. ISBN: 978-0-470-03214-5