這里介紹一個簡單的51單片機 4x4 Keypad 測試小程序，它同樣可以用在 4x1, 4x2 或者 4x3 Keypad 上。希望對大家有用。
- unsigned short kp, cnt, oldstate = 0;
- char txt[6];
- // Keypad module connections
- char keypadPort at P0;
- // End Keypad module connections
- // Lcd module connections
- sbit LCD_RS at P2_0_bit;
- sbit LCD_EN at P2_1_bit;
- sbit LCD_D4 at P2_2_bit;
- sbit LCD_D5 at P2_3_bit;
- sbit LCD_D6 at P2_4_bit;
- sbit LCD_D7 at P2_5_bit;
- // End Lcd module connections
- void main() {
- cnt = 0; // Reset counter
- Keypad_Init(); // Initialize Keypad
- Lcd_Init(); // Initialize Lcd
- Lcd_Cmd(_LCD_CLEAR); // Clear display
- Lcd_Cmd(_LCD_CURSOR_OFF); // Cursor off
- Lcd_Out(1, 1, "Key :"); // Write message text on Lcd
- Lcd_Out(2, 1, "Times:");
- do {
- kp = 0; // Reset key code variable
- // Wait for key to be pressed and released
- do
- // kp = Keypad_Key_Press(); // Store key code in kp variable
- kp = Keypad_Key_Click(); // Store key code in kp variable
- while (!kp);
- // Prepare value for output, transform key to it's ASCII value
- switch (kp) {
- //case 10: kp = 42; break; // '*' // Uncomment this block for keypad4x3
- //case 11: kp = 48; break; // '0'
- //case 12: kp = 35; break; // '#'
- //default: kp += 48;
- case 1: kp = 49; break; // 1 // Uncomment this block for keypad4x4
- case 2: kp = 50; break; // 2
- case 3: kp = 51; break; // 3
- case 4: kp = 65; break; // A
- case 5: kp = 52; break; // 4
- case 6: kp = 53; break; // 5
- case 7: kp = 54; break; // 6
- case 8: kp = 66; break; // B
- case 9: kp = 55; break; // 7
- case 10: kp = 56; break; // 8
- case 11: kp = 57; break; // 9
- case 12: kp = 67; break; // C
- case 13: kp = 42; break; // *
- case 14: kp = 48; break; // 0
- case 15: kp = 35; break; // #
- case 16: kp = 68; break; // D
- }
- if (kp != oldstate) { // Pressed key differs from previous
- cnt = 1;
- oldstate = kp;
- }
- else { // Pressed key is same as previous
- cnt++;
- }
- Lcd_Chr(1, 10, kp); // Print key ASCII value on Lcd
- if (cnt == 255) { // If counter varialble overflow
- cnt = 0;
- Lcd_Out(2, 10, " ");
- }
- WordToStr(cnt, txt); // Transform counter value to string
- Lcd_Out(2, 10, txt); // Display counter value on Lcd
- } while (1);
- }
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