MC_RATE_256_Hz
mcclock_addr->rega = (saved_rega & ~MC_BASE_RESET) | MC_RATE_256_Hz;
clk[MC_REGA].datum = MC_BASE_32_KHz | MC_RATE_256_Hz;
hzval = MC_RATE_256_Hz;
rate = MC_BASE_32_KHz | MC_RATE_256_Hz;