// key format : 2 bytes : keys group last addr byte + read mask
#define KEY_2ND     0x1220
#define KEY_MODE    0x1240
#define KEY_DEL     0x1280
#define KEY_ALPHA   0x1480
#define KEY_PLUS    0x1C02
#define KEY_MINUS   0x1C04
#define KEY_CLEAR   0x1C40
#define KEY_DOWN    0x1E01
#define KEY_LEFT    0x1E02
#define KEY_RIGHT   0x1E04
#define KEY_UP      0x1E08

uint8_t isKeyPressed(uint16_t key);
void startKeys();
void stopKeys();