Diff: keypad.cpp

Revision:

0:9a67044d749e

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/keypad.cpp	Sat Feb 25 14:21:11 2017 +0000
@@ -0,0 +1,115 @@
+#include "keypad.h"
+
+Keypad::Keypad(PinName row3, PinName row2, PinName row1, PinName row0,
+               PinName col3, PinName col2, PinName col1, PinName col0,
+               int debounce_ms):
+    _row0(row0), _row1(row1), _row2(row2), _row3(row3),
+    _cols(col0, col1, col2, col3)
+{
+    _debounce = debounce_ms;
+    _rows[0] = &_row0;
+    _rows[1] = &_row1;
+    _rows[2] = &_row2;
+    _rows[3] = &_row3;
+    for (int r = 0; r < row_count; r++)
+        _rows[r]->mode(PullUp);
+   // _cols.mode(OpenDrain);
+    _cols.output();
+}
+
+void Keypad::_setupFallTrigger(void)
+{
+    for (int r = 0; r < row_count; r++)
+        _rows[r]->fall(this, &Keypad::_callback);
+}
+
+void Keypad::Start(void)
+{
+    /* make the columns zero so they can pull rows down */
+    _cols = 0x00;
+}
+
+void Keypad::Stop(void)
+{
+    /* make the columns one so they cannot pull any rows down anymore */
+    _cols = ~0x00;
+}
+
+void Keypad::CallAfterInput(uint32_t (*fptr)(uint32_t index))
+{
+    _input.attach(fptr);
+    _setupFallTrigger();
+}
+
+int Keypad::DebouncedScan()
+{
+    /* debounce */
+    wait_ms(_debounce);
+
+    return Scan();
+}
+
+int Keypad::Scan()
+{
+    /* lookup row */
+    int r = -1;
+    for (r = 0; r < row_count; r++) {
+        if (*_rows[r] == 0)
+            break;
+    }
+
+    /* if we didn't find a valid row, return */
+    if (!(0 <= r && r < row_count))
+        return -1;
+
+    /* scan columns to find out which one pulls down the row */
+    int c = -1;
+    for (c = 0; c < col_count; c++) {
+        _cols = ~(1 << c);
+        if (*_rows[r] == 0)
+            break;
+    }
+
+    /* re-energize all columns */
+    Start();
+
+    /* if we didn't find a valid column, return */
+    if (!(0 <= c && c < col_count))
+        return -1;
+
+    return r * col_count + c;
+}
+
+int Keypad::DebouncedScanMultiple()
+{
+    /* debounce */
+    wait_ms(_debounce);
+
+    return ScanMultiple();
+}
+
+int Keypad::ScanMultiple()
+{
+    int res = 0;
+    for (int c = 0; c < col_count; c++) {
+        _cols = ~(1 << c);
+        for (int r = 0; r < row_count; r++) {
+            if (*_rows[r] == 0) {
+                res |= 1 << (r * col_count + c);
+            }
+        }
+    }
+
+    return res;
+}
+
+void Keypad::_callback()
+{
+    /* lookup */
+    int position = DebouncedScan();
+
+    /* call back a valid position */
+    if (position >= 0)
+        _input.call(position);
+}
+