National Instruments AT-AI-16XE-10, Programmer'S Manual

Page: 39 / 169

© National Instruments Corporation 3-1 AT-MIO E Series RLPM
3
Register Map and Descriptions
This chapter describes in detail the address and function of each of the AT E Series control
and status registers.
If you plan to use a programming software package such as NI-DAQ for DOS/Windows or
Lab Windows with your AT E Series board, you need not read this chapter. However, you will
gain added insight into your AT E Series board by reading this chapter.
Register Map
Table 3-1 shows the register map for the AT E Series boards and gives the register name, the
register offset address, the type of the register (read-only, write-only, or read-and-write), and
the size of the register in bits. Obtain the actual register address by adding the appropriate
register offset to the I/O base address of the AT E Series board.
Registers are grouped in the table by function. Each register group is introduced in the order
shown in Table 3-1, then described in detail, including a bit-by-bit description.
The DAQ-STC has 180 different registers. The more frequently used registers have been
given lower offset addresses and are shown in Table 3-1 as the DAQ-STC Register Group.
The advantage of having lower offset addresses is that they can be accessed directly. You can
access remaining registers in the DAQ-STC in the windowed mode. In this mode, the address
of the register is first written to the Window Address Register. The data to be written is then
written to the Window Data Register. Using windowed mode has the advantage of reducing
the address space of the board from 180 to 32 bytes. However, this reduced address space is
at the cost of two write operations to write data to or two read operations to read data from
a register.