SV_DIGITAL_OFF
v = sv_indirect_get(sc, SV_REG_DIGITAL_PWR) &~ SV_DIGITAL_OFF;
v = sv_indirect_get(sc, SV_REG_DIGITAL_PWR) | SV_DIGITAL_OFF;
sv_indirect_set(sc, SV_REG_DIGITAL_PWR, SV_DIGITAL_OFF);