For a variety of device families, NI has register level programming documentation available on the MHDDK product page: NI Measurement Hardware DDK (Driver Development Kit). These manuals are named either “Register Level Programming Manual” or “Technical Reference Manual”. In many cases, more than one manual is applicable to a device, where common components like the DAQ-STC or DAQ-DIO chips are used on a variety of devices.
RLP manuals contain descriptions of the individual devices and components on the devices. The descriptions include detailed information on the individual registers and bitfields on the device as well as information on programming the device for different operations using the registers. Information on initializing the device as well other general programming topics, such as RTSI, interrupts, DMA, is included. The completeness of the RLP documentation may vary some between the different product families. If you need additional information on a particular device contact your field engineer to discuss the possibility of extended support options.
For some hardware families, manuals have not been formally released and are therefore considered to be in beta status. These beta manuals are not available through the product page and need to be requested through your field engineer.