MR_CHRL
CLR(val, MR_CHMODE | MR_NBSTOP | MR_PAR | MR_CHRL | MR_CLKS);
#define CHRL_6BIT __SHIFTIN(3, MR_CHRL)
#define CHRL_7BIT __SHIFTIN(2, MR_CHRL)
#define CHRL_8BIT __SHIFTIN(1, MR_CHRL)