for (uint8_t col = 0; col < MATRIX_COLS; col++) { // 0-7
pull_column(col); // output hi on theline
_delay_us(5); // without this wait it won't read stable value.
for (uint8_t row = 0; row < MATRIX_ROWS; row++) { // 0-17
for (uint8_t col = 0; col < MATRIX_COLS; col++) { // 0-7
pull_column(col); // output hi on theline
_delay_us(5); // without this wait it won't read stable value.
for (uint8_t row = 0; row < MATRIX_ROWS; row++) { // 0-17