Flex_KBD.rar_Flex_KBD.rar_flex

/////////////////////////////////////////////////////////////////////////// //// Flex_KBD.C //// //// Generic keypad scan driver //// //// //// //// kbd_init() Must be called before any other function. //// //// //// //// c = kbd_getc(c) Will return a key value if pressed or /0 if not //// //// This function should be called frequently so as //// //// not to miss a key press. //// //// //// /////////////////////////////////////////////////////////////////////////// //Keypad connection: #define col0 PIN_B3 #define col1 PIN_B2 #define col2 PIN_B1 #define row0 PIN_B4 #define row1 PIN_B5 #define row2 PIN_B6 #define row3 PIN_B7 // Keypad layout: char const KEYS[4][3] = {{'1','2','3'}, {'4','5','6'}, {'7','8','9'}, {'*','0','#'}}; #define KBD_DEBOUNCE_FACTOR 16 // Set this number to apx n/333 where // n is the number of times you expect // to call kbd_getc each second void kbd_init() { } short int ALL_ROWS (void) { if (input (row0) & input (row1) & input (row2) & input (row3)) return (0); else return (1); } char kbd_getc( ) { static byte kbd_call_count; static short int kbd_down; static char last_key; static byte col; byte kchar; byte row; kchar='\0'; if(++kbd_call_count>KBD_DEBOUNCE_FACTOR) { switch (col) { case 0 : output_low(col0); output_high(col1); output_high(col2); break; case 1 : output_high(col0); output_low(col1); output_high(col2); break; case 2 : output_high(col0); output_high(col1); output_low(col2); break; } if(kbd_down) { if(!ALL_ROWS()) { kbd_down=false; kchar=last_key; last_key='\0'; } } else { if(ALL_ROWS()) { if(!input (row0)) row=0; else if(!input (row1)) row=1; else if(!input (row2)) row=2; else if(!input (row3)) row=3; last_key =KEYS[row][col]; kbd_down = true; } else { ++col; if(col==3) col=0; } } kbd_call_count=0; } return(kchar); }