The document discusses various applications for connecting output devices to the ports of an MCS-51 microcontroller. It describes how LEDs, 7-segment displays, LCD displays, transistors, relays, servo motors, and stepper motors can be connected to the ports and controlled through code. The ports each have a corresponding register that is used to send output signals to the devices or read input signals. Proper voltage levels and electrical connections are required to safely interface different devices with the microcontroller ports.

1. MICROCONTROLLER
MCS-51:
APPLICATIONS
Arkhom JODTANG
Civil Aviation Training Center
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2. Microcontroller Applications
Contents
 Operation voltage of MCS51
 Input / Output Port Register
 Connecting to various Output Devices
 LEDs
 Double LEDs
 RGB-LED
 7-Segment
 Matrix LCD Display
 Transistors (Current Amplification)
 Relays
 Servo Motors
 Stepper Motor
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3. Operation voltage of MCS51
 Operation voltage of MCS51 is 5 volts and
microcontroller work in digital concept, so all
input, output and communication devices to
attaching to port 1, 2 and 3 must work on 5
volts too.
 Except port 0 (Open collector), Load able to
connect with any level of supply able to drain
current to ground with port 0. Make sure that
drain current not over specification.
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4. Port 0 (Open collector property)
Make sure that drain current not over
specification.
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Microcontroller
Microcontroller
Relay

5. Input / Output Port Register
Relative register of Port 0 is P0
Relative register of Port 1 is P1
Relative register of Port 2 is P2
Relative register of Port 3 is P3
Any input, Output and Communication
devices connect to ports of MCS51
Input devices: current value of relative
register are equal to signal given from
input devices.
Such as MOV Acc, P2
Output Devices: Send data to
connected output devices by assign
value to relative register of ports.
Such as MOV P1, Acc
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6. Output Devices6

7. LEDs
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8. Double LEDs
ON: LED RED
MOV P2, #00000001B
ON: LED GREEN
MOV P2, #10000000B
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9. RGB LEDs
Ground
P1.0
P1.1
P1.2
With PWM the LED is turned
on and off many times per
second. By adjusting duty
percentage, the brightness of
each color the LED can be
controlled.
Image from: en.wikipedia.org
Image from: www.protostack.com/blog/2011/06/atmega168a-pulse-width-modulation-pwm/
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10. 7-Segment Display
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http://www.buildcircuit.com/digital-object-counter/

11. Matrix LCD Display
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12. Transistors (as a Current
Amplification)
Images form
http://www.w9xt.com/page_microdesign_pt7_transistor_switching.html
Coil
load
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13. Relay
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14. Servo Motor
Image from: www.arduitronics.com Image from: inexglobal.com
A servo is a device that will provide actuation for a mechanical system. They
come in many different shapes, sizes and detail specifications such Torque,
Speed and Capable rotation angle. The servo has three input wires. A pair
for a 4-6 VDC supply and a wire for signal control of the arm (PWM : Pulse
Width Modulation)
Supply (+)
Ground (0 V.)
Signal Control
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15. Servo Motor
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16. Servo Motor
https://robomark.wordpress.com/tag/robotics-servo-dspic/
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17. Servo Motor (RC Aircraft)
http://www.rcgroups.com/forums/showthread.php?t=1812847
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18. Servo Motor (RC Aircraft)
http://arxangelrc.blogspot.com/2014/04/volantexrc-firstar-impressive-mini-pusher-park-flyer.html
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19. Servo Motor (RC Aircraft)
http://arxangelrc.blogspot.com/2014/04/volantexrc-firstar-impressive-mini-pusher-park-flyer.html
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20. Stepper Motor
Image from: http://www.matrixtsl.com/courses/itm/index.php?n=AddingOutputs.StepperMotors Image from: https://www.super-tech.com/root/itm.asp?p1=ITM-MOTORS
Stepper motors work in a different way to the motors just discussed. Instead
of rotating smoothly, they do so in 'steps'. A control pulse is needed to make
the motor move to the next position. The advantage of this is that the
rotation can be precisely controlled - ten pulses means a rotation through
ten steps. With a conventional motor, it is pot-luck where it stops spinning.
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21. Stepper Motor
Image from: http://www.matrixtsl.com/courses/itm/index.php?n=AddingOutputs.StepperMotors
a
b
c
d
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22. Such as
• Dual Motor Driver
Circuit Module22

23. Dual Motor Driver
THIS L293D DRIVER MODULE IS A MEDIUM POWER MOTOR DRIVER
PERFECT FOR DRIVING DC MOTORS AND STEPPER MOTORS. IT
USES THE POPULAR L293D MOTOR DRIVER IC. IT CAN DRIVE 4 DC
MOTORS IN ONE DIRECTION, OR DRIVE 2 DC MOTORS IN BOTH
THE DIRECTIONS.
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