kbd_matrix.h : Matrix Keyboard module
[/drivers : Device drivers]

Full featured matrix (row/column) keyboard scanning module. More...

Data Structures
struct	kbd_matrix_key_state_t
	Key state bit mask (1 = key pressed; 0 = key released). More...
struct	kbd_matrix_key_t
	Linked list structure that describes which key has been pressed. More...
Defines
#define	KBD_MATRIX_MAX_NR_KEYS   56
	Maximum number of keys that can be handled by the module.
#define	KBD_MATRIX_NR_SAMPLES   4
	Number of samples that are necessary to debounce a keypress.
#define	KBD_MATRIX_MAX_NR_KEYS_PRESSED   4
	Maximum number of keys that may be pressed simultaneously.
#define	KBD_DELAY_BEFORE_REPEATING_KEY   200
	Delay before a pressed key will be repeated.
#define	KBD_KEY_REPEAT_DELAY   20
	Delay between pressed key repeats.
Typedefs
typedef void(*	kbd_matrix_on_key_event_t )(u8_t row, u8_t col, kbd_matrix_event_t event)
	Function that will be called when a key event has taken place.
typedef void(*	kbd_matrix_set_row_t )(u8_t row, bool_t active)
	Function that will be called to set a row output.
typedef bool_t(*	kbd_matrix_get_col_t )(u8_t col)
	Function that will be called to read a column input.
typedef void(*	kbd_matrix_delay_t )(bool_t active)
	Function that will be called for row column scanning delay.
Enumerations
enum	kbd_matrix_event_t { KBD_MATRIX_EVENT_RELEASED = 0, KBD_MATRIX_EVENT_PRESSED = 1 }
	Key event types. More...

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Detailed Description

Files: kbd_matrix.h & kbd_matrix.c

This module implements or makes provision for:

• Optimised matrix row/column key scanning
• Debouncing of key press and release
• n-key rollover
• Detection and elimination of "phantom" keys
• Key repetition (typematic)

See also:

• http://en.wikipedia.org/wiki/Computer_keyboard
• http://en.wikipedia.org/wiki/Rollover_(key)
• http://www.dribin.org/dave/keyboard/one_html/

Note:

This module is based on "kbmatrix.h" and "kbmatrix.c" found in the Atmel AT91 Software package

License:

 ----------------------------------------------------------------------------
         ATMEL Microcontroller Software Support 
 ----------------------------------------------------------------------------
 Copyright (c) 2008, Atmel Corporation

 All rights reserved.

 Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions are met:

 - Redistributions of source code must retain the above copyright notice,
 this list of conditions and the disclaimer below.

 Atmel's name may not be used to endorse or promote products derived from
 this software without specific prior written permission.

 DISCLAIMER: THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR
 IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE
 DISCLAIMED. IN NO EVENT SHALL ATMEL BE LIABLE FOR ANY DIRECT, INDIRECT,
 INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
 OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
 EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 ----------------------------------------------------------------------------

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Typedef Documentation

typedef void(* kbd_matrix_on_key_event_t)(u8_t row, u8_t col, kbd_matrix_event_t event)

Parameters:

[in]	row	Row address of key event
[in]	col	Column address of key event
[in]	event	Key event type: PRESSED or RELEASED

Definition at line 149 of file kbd_matrix.h.

typedef void(* kbd_matrix_set_row_t)(u8_t row, bool_t active)

Parameters:

[in]	row	Specifies which row that should be set
[in]	active	Specifies that row should be activated (normally active low)

Definition at line 158 of file kbd_matrix.h.

typedef bool_t(* kbd_matrix_get_col_t)(u8_t col)

Return values:

	TRUE	Key is being pressed
	FALSE	Key is not pressed (released)

Definition at line 166 of file kbd_matrix.h.

typedef void(* kbd_matrix_delay_t)(bool_t active)

If a row is set to active, there is a certain delay before the columns should be sampled.

If a row is set to inactive, there is a certain delay before the columns return to their inactive state.

Parameters:

[in]

active

Specifies that row should be activated (normally active low)

Definition at line 180 of file kbd_matrix.h.

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Enumeration Type Documentation

enum kbd_matrix_event_t

Enumerator:

KBD_MATRIX_EVENT_RELEASED	Key has been released.
KBD_MATRIX_EVENT_PRESSED	Key has been pressed.

Definition at line 135 of file kbd_matrix.h.

{
    KBD_MATRIX_EVENT_RELEASED = 0,  ///< Key has been released
    KBD_MATRIX_EVENT_PRESSED  = 1   ///< Key has been pressed
} kbd_matrix_event_t;