NI_M_AO_REF_ATTENUATION_REG
ni_writeb(dev, 0, NI_M_AO_REF_ATTENUATION_REG(chan));
ni_writeb(dev, 0, NI_M_AO_REF_ATTENUATION_REG(chan));
NI_M_AO_REF_ATTENUATION_REG(chan));
NI_M_AO_REF_ATTENUATION_REG(chan));
NI_M_AO_REF_ATTENUATION_REG(channel));