MC_REGB_BINARY
mc146818_write(sc, MC_REGB, MC_REGB_BINARY | MC_REGB_24HR);
MC_REGB_PIE | MC_REGB_SQWE | MC_REGB_BINARY | MC_REGB_24HR);
mc146818_write(sc, MC_REGB, MC_REGB_BINARY | MC_REGB_24HR);
rtc_write_reg(sc, MC_REGB, MC_REGB_BINARY | MC_REGB_24HR);