Fork without short circuits
Fork of keypad by
No extra hardware is needed besides the wires and switches. The columns are outputs configured with open drain. The rows are inputs configured with pull up resistors. A key press pulls down its row. With scanning the column is determined thereafter.
See SaveKeypad for an example usage.
Revision 16:a9feaa7ac039, committed 2012-11-08
- Comitter:
- gj_schoneveld
- Date:
- Thu Nov 08 19:04:08 2012 +0000
- Parent:
- 15:873a9a452ef1
- Commit message:
- Updated Debounce
Changed in this revision
keypad.cpp | Show annotated file Show diff for this revision Revisions of this file |
diff -r 873a9a452ef1 -r a9feaa7ac039 keypad.cpp --- a/keypad.cpp Sun Nov 04 09:56:24 2012 +0000 +++ b/keypad.cpp Thu Nov 08 19:04:08 2012 +0000 @@ -44,16 +44,9 @@ int Keypad::DebouncedScan() { /* debounce */ - int key1 = Scan(); - wait_ms(_debounce); - - int key2 = Scan(); - - if (key1 != key2) - return -1; - else - return key1; + + return Scan(); } int Keypad::Scan() @@ -69,7 +62,7 @@ if (!(0 <= r && r < row_count)) return -1; - /* scan columns to find out which one pulls down the row */ + /* scan columns to find out which one pulls down the row */ int c = -1; for (c = 0; c < col_count; c++) { _cols = ~(1 << c); @@ -86,21 +79,18 @@ return r * col_count + c; } + int Keypad::DebouncedScanMultiple() { /* debounce */ - int key1 = ScanMultiple(); - wait_ms(_debounce); - - int key2 = ScanMultiple(); - - return key1 & key2; + + return ScanMultiple(); } int Keypad::ScanMultiple() { - int res = 0; + int res = 0; for (int c = 0; c < col_count; c++) { _cols = ~(1 << c); for (int r = 0; r < row_count; r++) { @@ -109,7 +99,7 @@ } } } - + return res; } @@ -117,7 +107,7 @@ { /* lookup */ int position = DebouncedScan(); - + /* call back a valid position */ if (position >= 0) _input.call(position);