Lab 8

Lab 8 - debounce and encode a pressed key on the keyboard...

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Keyboard Interfacing ± There are several types of keyboards available for computer usage. Some of the most common types are: ² Mechanical switches ² Membrane switches ² Capacitive switches ² Hall effect key switches
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Keyboard Interfacing ± Most keyboards are organized as a matrix of rows and columns. Getting data from the keyboard requires the following steps: ² Detect a key press. ² Debounce the key press. ² Encode the key.
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Keyboard Interfacing
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Keyboard Interfacing ± This flow chart shows the process necessary to detect,
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Unformatted text preview: debounce, and encode a pressed key on the keyboard. Detecting a Key Detecting a Row Detecting a Row Encoding a Key ± Encoding the key press: ² Find the row and column positions (obtained from the key detection routine). ² Calculate the offset using the following formula: OFFSET = ( row * 8 ) + column ± 8 is the number of columns in the keyboard matrix. ² Find the proper character using the offset, the base address of the conversion table and XLATB instruction....
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This note was uploaded on 01/24/2012 for the course EE 3751 taught by Professor Desouza during the Spring '04 term at LSU.

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Lab 8 - debounce and encode a pressed key on the keyboard...

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