/* scan all key states on matrix */
uint8_t matrix_scan(void);
/* whether modified from previous scan. used after matrix_scan. */
-bool matrix_is_modified(void);
+bool matrix_is_modified(void) __attribute__ ((deprecated));
/* whether a swtich is on */
bool matrix_is_on(uint8_t row, uint8_t col);
/* matrix state on row */