MICRO-CONTROLLER
Micro-controller is a on-chip computer or single chip computer. This
small device is used to control event, processes and objects. Another term to
describe micro-controller is embedded controller because the microcontroller
and its support circuits are often built into, or embedded in, devices they
control. Any device that measures, stores, controls, calculates and displays
information is a candidate for putting micro-controller inside. Micro-controller contains memory, I/O interfaces in addition to the C.P.U. Because the amount of
memory and interfaces is limited so micro-controllers are used for smaller
system. In this project, micro-controller 8051 is used.
Block Diagram of
MICROCONTROLLER 8051
PIN DISCRIPTION
VCC - Supply voltage
GND - Ground
PORT
1 - Port 1 is an 8 – bit bi directional I/O
port. Port pins p1.2 to
P1.7
provides internal pull - ups. P1.0 and P1.1 require
external
pull- ups. P1.0 and P1.1 also serves as positive input
and negative
input.
PORT
3 - Port 3 pins P3.0 to P3.5, P3.7 are seven
bi directional I/O
pins with
internal pull-ups.P3.6 is hard wired as an input to
output of
the on chip comparator and is not accessible with
general
purpose I/O pin.
Port pin
|
Alternate function
|
|
P3.0
|
RXD (SERIAL INPUT PORT)
|
|
P3.1
|
TXD (SERIAL OUTPUT
PORT)
|
|
P3.2
|
INT0(INTERNAL INTERRUPT
O
|
|
P3.3
|
INT 1 (EXTERNAL
INTURREPT 1)
|
|
P3.4
|
T0 (TIMER 0)
|
|
P3.5
|
T1 (TIMER 1)
|
|
TABLE 2.2 PIN FUNCTIONS OF
MICROCONTROLLER 8051
Port 3 also receives some control signals for flash programming and
verification.
RST - Reset input
XTAL1 - Input to the inverting oscillator amplifier
and input to the internal
Clock
operating circuit.
XTAL2 - Output from inverting oscillator amplifier.
copyright by
sh mohd faiz
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