AN887 Datasheet, PDF (1/12 Pages) STMicroelectronics – MICROCONTROLLERS MADE EASY

AN887
APPLICATION NOTE
MICROCONTROLLERS MADE EASY
by Microcontroller Division Applications
WHAT IS A MICROCONTROLLER?
A few years ago, system control functions were implemented using logic components and
were usually large, heavy boxes. Later on, microprocessors were used and the entire con-
troller could fit onto a small circuit board. As the process of miniaturization continued, all of the
components needed for a controller were built right onto one chip. By only including the fea-
tures specific to the task, cost is relatively low.
A typical microcontroller has bit manipulation instructions, easy7 and direct access to I/O, and
quick and efficient interrupt processing. Therefore, a microcontroller is a highly integrated
device which includes, on one chip, all or most of the parts needed to perform an application
control function.
Microcontrollers come in many varieties. Depending on the power and features that are
needed, customers might choose a 4, 8, 16, or 32 bit microcontroller.
Figure 1. Typical MCU Block Diagram
CONTAINS
PROGRAM
AND DATA
ROM
RAM
CONTAINS
TEMPORARY
DATA
EXECUTES PROGRAM
MANAGES EVENTS
SIGNAL GENERATION
EVENT COUNTING
APPLICATION TIMEBASE
CPU
TIMER
EEPROM
A/ D
CONVERTER
CONTAINS
PERMANENT
DATA
ANALOG DATA
ACQUISITION
PERIPHERAL
INTERFACE
I/O PORT
SERIAL
INTERFACE
SENDS AND
RECEIVES
DATA
VR02101A
ROM (Read Only Memory)
ROM is usually used to store program instructions. ROM is the least expensive mean of
storing a program in a microcontroller, especially for high volume manufacturing.
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