MK_CSR_READ
chiptime[MK_CSR] |= MK_CSR_READ; /* enable read (stop time) */
chiptime[MK_CSR] &= ~MK_CSR_READ; /* time wears on */
mclock[MK_CSR] |= MK_CSR_READ;
mclock[MK_CSR] &= ~MK_CSR_READ;