Chapter 10. Button

The Button module provides functions to read on-board button/key status. The Button module periodically scans the buttons, in the event loop. When a button is pressed, an integer corresponding to the button is stored in the FIFO. This can be read from the FIFO, and processed at a later time.

The Button module functions are declared in button.h. The following example reads the button status and prints it on the LCD.

Listing 10.1. Reading Buttons

#include <board.h>
#include <lcd.h>
#include <button.h>

void main()
{
        board_init();
        lcd_init();
        button_init();

        lcd_puts("Press any key\n");
        while (1) {
                char key;
                key = button_getc();

                switch (key) {
                case 0:
                        lcd_puts("Key 1 Pressed\n");
                        break;
                case 1:
                        lcd_puts("Key 2 Pressed\n");
                        break;
                case 2:
                        lcd_puts("Key 3 Pressed\n");
                        break;
                case 3:
                        lcd_puts("Key 4 Pressed\n");
                        break;
                }
        }
}


gfx_draw_string		button_init