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CIRCUIT DESCRIPTION
This one is a simple timing control project that executes many
times-based
tasks.
An Atmel Micro controller has become our target micro
controller.
Micro controller kit is interface with our PC. The circuit
diagram shows the
interfacing the micro controller with our PCs LPT port pin
2,3,4,5,6 & 25.
LPT port pin 2 to pin 9 are output pin and 25 pin is ground pin.
LPT port pin
2 is connected to pin no 1 MCT2E through resistor 270 ohms and
MCT2E
pin 2 is connected to LPT port pin 25. Simultaneously all MCT2E
is
connected to all LPT port pin 3 to 6 and pin 25 (MCT2E is a
optocoupler IC)
to protect the PC and micro controller kit) All pin 5 of MCT2E
is connected
to Vcc of power supply and all pin 4 of MCT2E is connected to
its micro
controller port P 1. P 1.0,P 1.1, P 1.2, P1.3, P1.4 respectively
through
resistor 1k.
Capacitor 10 micro Farad 50V is connected to pin 9 through
resistor 10K
ohms and crystal 12 MHz and 33 pico Farad is connected is
connected to pin
18 and pin 19 of micro controller. The micro controller port 2
of pin 21. 22,
23, 24 and 25 (P2.3, P2.4, P2.5, P2.6, P2,7) is connected to all
MCT2E pin
2, of all through resistor 270 ohm and pin 1 is connected to
board. Pin 4 is
connected the box of transistor BC 457 through resistor 10K and
collector of
transistor is connected to 12V through resistor 270 ohm and R1Y5
(12V).
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The data from the PC is given to micro controller. The micro
controller then
calculates the bit and proceeds further. The control will be
transferred to the
relay unit. As per the data fetched from the PC the micro
controller operates
on it. Then the power board controls all the room power
supply.
The circuit is given the power supply, using the Transformer. It
is given 230
V AC supply. Four diodes are connected to the transformer.
Voltage Regulators are used to regulate the voltage. The
following voltage
regulators are used to generate various outputs :
7812 regulator generates a +12V supply.
7912 regulator generates a 12V supply.
7809 regulator generates +9V supply.
7805 regulator generates +5V vcc supply.
- 12V is given to the relay.
- +5V, vcc are given to the Pin No. 31,40 of the Micro
Controller 89C51.
