566
Digital Electronics
ROM
Microprocessor
EEPROM
RAM
Input
and
Output
Ports
Serial
I/O
Parallel
I/O
Timer
PWM
Input
and
Output
Ports
A/D
Converter
D/A
Converter
(a)
ROM
EEPROM
RAM
Serial
I/O
Parallel
I/O
Timer
PWM
A/D
Converter
CPU
Core
Microcontroller
(b)
Figure 14.1 Microprocessor versus microcontroller: (a) microprocessor configuration; (b) microcontroller
configuration.
unit with some general-purpose registers. A microprocessor-based system also has RAM, ROM, I/O
ports and other peripheral devices to make it a complete functional unit, but all these components
are external to the microprocessor chip. While a microprocessor-based system is a general-purpose
system that may be programmed to do any of the large number of functions it is capable of doing,