/* matrix state(1:on, 0:off) */
static matrix_row_t matrix[MATRIX_ROWS];
+/*
+ * matrix state(1:on, 0:off)
+ * contains the raw values without debounce filtering of the last read cycle.
+ */
+static matrix_row_t raw_matrix[MATRIX_ROWS];
// Debouncing: store for each key the number of scans until it's eligible to
// change. When scanning the matrix, ignore any changes in keys that have
// initialize matrix state: all keys off
for (uint8_t i=0; i < MATRIX_ROWS; i++) {
matrix[i] = 0;
+ raw_matrix[i] = 0;
for (uint8_t j=0; j < MATRIX_COLS; ++j) {
debounce_matrix[i * MATRIX_COLS + j] = 0;
}
// Returns a matrix_row_t whose bits are set if the corresponding key should be
// eligible to change in this scan.
-matrix_row_t debounce_mask(uint8_t row) {
+matrix_row_t debounce_mask(matrix_row_t rawcols, uint8_t row) {
matrix_row_t result = 0;
- for (uint8_t j=0; j < MATRIX_COLS; ++j) {
- if (debounce_matrix[row * MATRIX_COLS + j]) {
- --debounce_matrix[row * MATRIX_COLS + j];
+ matrix_row_t change = rawcols ^ raw_matrix[row];
+ raw_matrix[row] = rawcols;
+ for (uint8_t i = 0; i < MATRIX_COLS; ++i) {
+ if (debounce_matrix[row * MATRIX_COLS + i]) {
+ --debounce_matrix[row * MATRIX_COLS + i];
} else {
- result |= (1 << j);
+ result |= (1 << i);
}
- }
- return result;
-}
-
-// Report changed keys in the given row. Resets the debounce countdowns
-// corresponding to each set bit in 'change' to DEBOUNCE.
-void debounce_report(matrix_row_t change, uint8_t row) {
- for (uint8_t i = 0; i < MATRIX_COLS; ++i) {
if (change & (1 << i)) {
debounce_matrix[row * MATRIX_COLS + i] = DEBOUNCE;
}
}
+ return result;
+}
+
+matrix_row_t debounce_read_cols(uint8_t row) {
+ // Read the row without debouncing filtering and store it for later usage.
+ matrix_row_t cols = read_cols(row);
+ // Get the Debounce mask.
+ matrix_row_t mask = debounce_mask(cols, row);
+ // debounce the row and return the result.
+ return (cols & mask) | (matrix[row] & ~mask);;
}
uint8_t matrix_scan(void)
select_row(i + MATRIX_ROWS_PER_SIDE);
// we don't need a 30us delay anymore, because selecting a
// left-hand row requires more than 30us for i2c.
- matrix_row_t mask = debounce_mask(i);
- matrix_row_t cols = (read_cols(i) & mask) | (matrix[i] & ~mask);
- debounce_report(cols ^ matrix[i], i);
- matrix[i] = cols;
+
+ // grab cols from left hand
+ matrix[i] = debounce_read_cols(i);
// grab cols from right hand
- mask = debounce_mask(i + MATRIX_ROWS_PER_SIDE);
- cols = (read_cols(i + MATRIX_ROWS_PER_SIDE) & mask) | (matrix[i + MATRIX_ROWS_PER_SIDE] & ~mask);
- debounce_report(cols ^ matrix[i + MATRIX_ROWS_PER_SIDE], i + MATRIX_ROWS_PER_SIDE);
- matrix[i + MATRIX_ROWS_PER_SIDE] = cols;
+ matrix[i + MATRIX_ROWS_PER_SIDE] = debounce_read_cols(i + MATRIX_ROWS_PER_SIDE);
+
unselect_rows();
}