Button Library
The Button Library provides routines for detecting button presses and debouncing (eliminating the influence of contact flickering upon pressing a button).
Library Routines
Button
Prototype |
unsigned short Button(unsigned short *port, unsigned short pin, unsigned short time, unsigned short active_state); |
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Returns |
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Description |
Function eliminates the influence of contact flickering upon pressing a button (debouncing). Parameter |
Requires |
Button pin must be configured as input. |
Example |
Example reads RB0, to which the button is connected; on transition from 1 to 0 (release of button), PORTD is inverted: bit oldstate; // Old state flag void main() { ANSEL = 0; // Configure AN pins as digital I/O ANSELH = 0; C1ON_bit = 0; // Disable comparators C2ON_bit = 0; TRISB0_bit = 1; // set RB0 pin as input TRISC = 0x00; // Configure PORTC as output PORTC = 0xAA; // Initial PORTC value oldstate = 0; do { if (Button(&PORTB, 0, 1, 1)) { // Detect logical one oldstate = 1; // Update flag } if (oldstate && Button(&PORTB, 0, 1, 0)) { // Detect one-to-zero transition PORTC = ~PORTC; // Invert PORTC oldstate = 0; // Update flag } } while(1); // Endless loop } |
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