7 segment interface with avr microcontroller

7 segment interface with avr microcontroller

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  7 SEGMENT INTERFACEWITH AVR MICROCONTROLLER A. D. Patel Institute Of Technology EC :- Sem V Present By :- Pratik Makadia (130010111017) 19 October 2015 1
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  Introduction  Seven segmentdisplays are very common for electronic product to display numerical output.  Many common devices like calculators, watches, electronic weighing scales, ovens etc use them.  You must have also seen in our ADIT lifts display the current floor numbers in seven segment displays. 19 October 2015 2
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  Fundamentals  A seven-segmentdisplay is so named because it is divided into seven different segments that can be switched on or off.  The different combination of these segments switched on produces different English numbers.  The display also has a decimal point. 19 October 2015 3
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   The figureshows a seven segment display and the names of the various segments.  For example if you want to display number 4 then segments that will be ‘on’ are {f, g, b, c} while rest are ‘off’. Basically the seven segments are just LEDs.  The one common end of all the leds are connected while the rest are available.  Depending on whether anode or cathode of all the leds are common they are of two types. 19 October 2015 4
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  1) Common anode 19October 2015 5 2) Common cathode
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  PIN Configuration  thesedisplays should have nine pin( one for each segment + decimal point +common).  but the available modules have two pins for common.  They are internally connected. So they have total of 10 PINs. 19 October 2015 6
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  Interfacing with MCU Interfacing these displays are same as interfacing LEDs with MCU.  I have interfaced a common anode(+) 7 segment display with PORTD of AVR using 8-PIN connectors.  The segments will be "on" when levels on the PORT is low, that is 0. 19 October 2015 7
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  Block Diagram OfInterfacing 19 October 2015 8
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  Table for all16 hexadecimal digits and values for all segment to need turn on the proper segment. Digit Hex Value g f e d c b a 0 0x3F 0 1 1 1 1 1 1 1 0x06 0 0 0 0 1 1 0 2 0x5B 1 0 1 1 0 1 1 3 0x4F 1 0 0 1 1 1 1 4 0x66 1 1 0 0 1 1 0 5 0x6D 1 1 0 1 1 0 1 6 0x7D 1 1 1 1 1 0 1 7 0x07 0 0 0 0 1 1 1 19 October 2015 9 Digit Hex Value g f e d c b a 8 0x7F 1 1 1 1 1 1 1 9 0x6F 1 1 0 1 1 1 1 A 0x77 1 1 1 0 1 1 1 B 0x7C 1 1 1 1 1 0 0 C 0x39 0 1 1 1 0 0 1 D 0x5E 1 0 1 1 1 1 0 E 0x79 1 1 1 1 0 0 1 F 0x71 1 1 1 0 0 0 1
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  Programming  These displaysare very easy to program in C.  The controller is initialized by sending three commands: 1) Turning on its internal oscillator 2) Enabling display output 3) Setting the brightness level  Brightness is adjusted from 0 (dimmest) to 15 (brightest). 19 October 2015 10
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