06 interfacing keypad 4x4.2016
TRANSCRIPT
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06-Interfacing 4x4 keypad.
By : Mohamed Fawzy
Programming AVR Microcontrollers
© Mohamed F.A.B 2015
Lecture Notes:
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o Set Your Phone To Vibration Mode.
o Ask any time.
o During labs, Feel Free To Check Any Materials or
Internet.
o Slides are self content.
o Feel Free To Share This Materials With Your Friends.
o Work Hard For Achieving Most Of This Course.
© Mohamed F.A.B 2015
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Don't Forget !!!!
© Mohamed F.A.B 2015
Any Expert Was Once A Beginner
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Lesson(12).
© Mohamed F.A.B 2015
Lesson (11):
Interfacing Keypad 4*4 .
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Lesson (11) Topics.
© Mohamed F.A.B 2015
► Why Matrix Keypad.
► Matrix Keypad Theory.
► Scanning Key pressed.
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Why Matrix Keypad?
© Mohamed F.A.B 2015
o To reduce the microcontroller I/O pin usage, keyboards
are organized in a matrix of rows and columns.
o The CPU accesses both rows and columns through ports.
o When a key is pressed, a row and a column make a
contact; otherwise, there is no connection between
rows and columns.
o A 4 × 4 matrix connected to two ports. The rows are
connected to an output port and the columns are
connected to an input port.
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Keypad Theory.
© Mohamed F.A.B 2015
.
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Scanning Key pressed.
© Mohamed F.A.B 2015
Configurations for keypad:
Initialization for keypad PORT:
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Scanning Key pressed. Cont’
© Mohamed F.A.B 2015
Scanning one row:
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Scanning Key pressed. Cont’
© Mohamed F.A.B 2015
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Questions:
© Mohamed F.A.B 2015
