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Merge pull request #5031 from dhalbert/keymatrix-scan-false-readings

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Make KeyMatrix row output switch faster
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Dan Halbert 2021-07-21 12:03:17 -04:00 committed by GitHub
commit 626b06f8a7
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1 changed files with 7 additions and 2 deletions
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9
shared-module/keypad/KeyMatrix.c
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@ -153,8 +153,9 @@ void keypad_keymatrix_scan(keypad_keymatrix_obj_t *self) {
for (size_t row = 0; row < common_hal_keypad_keymatrix_get_row_count(self); row++) { for (size_t row = 0; row < common_hal_keypad_keymatrix_get_row_count(self); row++) {
// Switch this row to an output and set level appropriately // Switch this row to an output and set level appropriately
// Set low if columns_to_anodes is true, else set high. // Set low if columns_to_anodes is true, else set high.
digitalio_digitalinout_obj_t *row_dio = self->row_digitalinouts->items[row];
common_hal_digitalio_digitalinout_switch_to_output( common_hal_digitalio_digitalinout_switch_to_output(
self->row_digitalinouts->items[row], !self->columns_to_anodes, DRIVE_MODE_PUSH_PULL); row_dio, !self->columns_to_anodes, DRIVE_MODE_PUSH_PULL);
for (size_t column = 0; column < common_hal_keypad_keymatrix_get_column_count(self); column++) { for (size_t column = 0; column < common_hal_keypad_keymatrix_get_column_count(self); column++) {
mp_uint_t key_number = row_column_to_key_number(self, row, column); mp_uint_t key_number = row_column_to_key_number(self, row, column);
@ -175,8 +176,12 @@ void keypad_keymatrix_scan(keypad_keymatrix_obj_t *self) {
} }
} }
// Done with this row. Set its pin to its resting pull value briefly to shorten the time it takes
// to switch values. Just switching to an input with a (relatively weak) pullup/pulldown
// causes a slight delay in the output changing, which can cause false readings.
common_hal_digitalio_digitalinout_set_value(row_dio, self->columns_to_anodes);
// Switch the row back to an input, pulled appropriately // Switch the row back to an input, pulled appropriately
common_hal_digitalio_digitalinout_switch_to_input( common_hal_digitalio_digitalinout_switch_to_input(
self->row_digitalinouts->items[row], self->columns_to_anodes ? PULL_UP : PULL_DOWN); row_dio, self->columns_to_anodes ? PULL_UP : PULL_DOWN);
} }
} }