From 82aa9ad4a567695d1f7d0b1e36bf8563d2967813 Mon Sep 17 00:00:00 2001 From: Michael Stapelberg Date: Wed, 19 May 2021 22:43:36 +0200 Subject: [PATCH] matrix: wait for row signal to go HIGH for every row (#12945) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit I noticed this discrepancy (last row of the matrix treated differently than the others) when optimizing the input latency of my keyboard controller, see also https://michael.stapelberg.ch/posts/2021-05-08-keyboard-input-latency-qmk-kinesis/ Before this commit, when tuning the delays I noticed ghost key presses when pressing the F2 key, which is on the last row of the keyboard matrix: the dead_grave key, which is on the first row of the keyboard matrix, would be incorrectly detected as pressed. After this commit, all keyboard matrix rows are interpreted correctly. I suspect that my setup is more susceptible to this nuance than others because I use GPIO_INPUT_PIN_DELAY=0 and hence don’t have another delay that might mask the problem. --- quantum/matrix.c | 8 ++------ quantum/split_common/matrix.c | 8 ++------ 2 files changed, 4 insertions(+), 12 deletions(-) diff --git a/quantum/matrix.c b/quantum/matrix.c index c027b7bf27a..34d6af2e6df 100644 --- a/quantum/matrix.c +++ b/quantum/matrix.c @@ -116,9 +116,7 @@ static bool read_cols_on_row(matrix_row_t current_matrix[], uint8_t current_row) // Unselect row unselect_row(current_row); - if (current_row + 1 < MATRIX_ROWS) { - matrix_output_unselect_delay(); // wait for row signal to go HIGH - } + matrix_output_unselect_delay(); // wait for all Col signals to go HIGH // If the row has changed, store the row and return the changed flag. if (current_matrix[current_row] != current_row_value) { @@ -178,9 +176,7 @@ static bool read_rows_on_col(matrix_row_t current_matrix[], uint8_t current_col) // Unselect col unselect_col(current_col); - if (current_col + 1 < MATRIX_COLS) { - matrix_output_unselect_delay(); // wait for col signal to go HIGH - } + matrix_output_unselect_delay(); // wait for all Row signals to go HIGH return matrix_changed; } diff --git a/quantum/split_common/matrix.c b/quantum/split_common/matrix.c index f8de17809d1..039e7d97738 100644 --- a/quantum/split_common/matrix.c +++ b/quantum/split_common/matrix.c @@ -130,9 +130,7 @@ static bool read_cols_on_row(matrix_row_t current_matrix[], uint8_t current_row) // Unselect row unselect_row(current_row); - if (current_row + 1 < MATRIX_ROWS) { - matrix_output_unselect_delay(); // wait for row signal to go HIGH - } + matrix_output_unselect_delay(); // wait for all Col signals to go HIGH // If the row has changed, store the row and return the changed flag. if (current_matrix[current_row] != current_row_value) { @@ -192,9 +190,7 @@ static bool read_rows_on_col(matrix_row_t current_matrix[], uint8_t current_col) // Unselect col unselect_col(current_col); - if (current_col + 1 < MATRIX_COLS) { - matrix_output_unselect_delay(); // wait for col signal to go HIGH - } + matrix_output_unselect_delay(); // wait for all Row signals to go HIGH return matrix_changed; }