Diff: keypad.h

Revision:

12:5cb9ffad1ad7

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/keypad.h	Fri May 06 13:10:20 2016 +0000
@@ -0,0 +1,175 @@
+/**
+ * Driver for Keypad devices
+ * @author Gedeon Nyengele
+ * @version 1.0
+ * @date 5/7/2015
+ */
+
+#ifndef KEYPAD_H
+#define KEYPAD_H
+#include "mbed.h"
+
+template<unsigned char nRows, unsigned char nCols>
+class Keypad
+{
+public:
+    Keypad(char matrix[nRows][nCols], BusInOut* rows, BusInOut* cols);
+    char getKeyChar();  // Get the value of the pressed key
+    char getKeyChar(void (*wait_ms_fn)(int millis));
+    ~Keypad(){};
+    enum BTN_STATE { RELEASE, DEBOUNCE_PRESS, PRESSED, DEBOUNCE_RELEASE, DONE };
+
+private:
+    int getKey();
+
+protected:
+    char _matrix[nRows][nCols];
+    BusInOut* _cols;
+    BusInOut* _rows;
+};
+
+/** --------------------------------------------------------------------------
+ * Constructor
+ *----------------------------------------------------------------------------
+ */
+template<unsigned char nRows, unsigned char nCols>
+Keypad<nRows, nCols>::Keypad(char matrix[nRows][nCols], BusInOut* rows, BusInOut* cols)
+{
+
+    // Copy keypad matrix
+    for (int i = 0; i < nRows; i++) {
+        for (int j = 0; j < nCols; j++) {
+            _matrix[i][j] = matrix[i][j];
+        }
+    }
+
+    // Create data bus for row pins
+    _rows = rows;
+
+    // Create data bus for column pins
+    _cols = cols;
+}
+
+template<unsigned char nRows, unsigned char nCols>
+char Keypad<nRows, nCols>::getKeyChar(void (*wait_ms_fn)(int millis)) {
+    int key;
+    int temp_key = 0;
+    bool done = false;
+    BTN_STATE state = RELEASE;
+
+    while(!done) {
+        switch(state) {
+            case RELEASE:
+                key = getKey();
+                if (key < 0) {
+                    state = RELEASE;
+                } else {
+                    state = DEBOUNCE_PRESS;
+                    temp_key = key;
+                }
+                break;
+
+            case DEBOUNCE_PRESS:
+                if (wait_ms_fn == 0) wait_ms(30);
+                else wait_ms_fn(30);
+                key = getKey();
+                if (key == temp_key) {
+                    state = PRESSED;
+                } else {
+                    state = RELEASE;
+                }
+                break;
+
+            case PRESSED:
+                key = getKey();
+                if (key == temp_key) {
+                    state = PRESSED;
+                } else {
+                    state = DEBOUNCE_RELEASE;
+                }
+                break;
+
+            case DEBOUNCE_RELEASE:
+                if (wait_ms_fn == 0) wait_ms(30);
+                else wait_ms_fn(30);
+                key = getKey();
+                if (key == temp_key) {
+                    state = PRESSED;
+                } else {
+                    state = RELEASE;
+                    done  = true;
+                }
+        }
+    }
+
+    return (char) temp_key;
+}
+
+/** --------------------------------------------------------------------------
+ * Get Key Character
+ *----------------------------------------------------------------------------
+ */
+template<unsigned char nRows, unsigned char nCols>
+char Keypad<nRows, nCols>::getKeyChar()
+{
+    return getKeyChar(0);
+}
+
+
+// HELPER FUNCTIONS
+
+template<unsigned char nRows, unsigned char nCols>
+int Keypad<nRows, nCols>::getKey()
+{
+    int rowVal = (1 << nRows) - 1;
+    int colVal = (1 << nCols) - 1;
+    int row = -1, col = -1;
+    unsigned int temp;
+
+    // Read rows
+    _cols->output();
+    _cols->write(0);
+    _rows->input();
+    _rows->mode(PullUp);
+    wait_us(5);
+    rowVal = _rows->read();
+
+    //Read colums
+    _rows->output();
+    _rows->write(0);
+    _cols->input();
+    _cols->mode(PullUp);
+    wait_us(5);
+    colVal = _cols->read();
+
+    // Signal no key press
+    if (rowVal == ((1 << nRows) - 1) || colVal == ((1 << nCols) - 1) )
+        return -1;
+
+    // Find row number
+    temp = rowVal ^ ((1 << nRows) - 1);
+    for (int i = 0; i < nRows; i++) {
+
+        if ((temp & (1 << i)) > 0) {
+            row = i;
+            break;
+        }
+    }
+    
+    // Find column number
+    temp = colVal ^ ((1 << nCols) - 1);
+    for (int i = 0; i < nCols; i++) {
+        if ((temp & (1 << i)) > 0) {
+            col = i;
+            break;
+        }
+    }
+
+    if (row == -1 || col == -1)
+        return -1;
+    else {
+        return _matrix[row][col];
+    }
+}
+
+#endif // KEYPAD_H
\ No newline at end of file