© National Instruments Corporation
4-1
SCXI-1160 User Manual
Chapter 4
Register Descriptions
This chapter describes in detail the SCXI-1160 Address Handler, the Module ID Register, the
Data Register, the Status Register, and the Slot 0 registers.
Note: If you plan to use a programming software package such as NI-DAQ, LabWindows, or
LabVIEW with your SCXI-1160 board, you do not need to read this chapter.
Register Description
Register Description Format
This register description chapter discusses each of the SCXI-1160 registers and the Slot 0
registers. A detailed bit description of each register is given. The individual register description
gives the type, word size, and bit map of the register, followed by a description of each bit.
The register bit map shows a diagram of the register with the MSB shown on the left (bit 31 for a
32-bit register, bit 15 for a 16-bit register, and bit 7 for an 8-bit register) and the LSB shown on
the right (bit 0). A rectangle is used to represent each bit. Each bit is labeled with a name inside
its rectangle. An asterisk (*) after the bit name indicates that the bit is inverted (negative logic).
The Module ID register has a unique format and is described in the Module ID Register section.
In many of the registers, several bits are labeled with an X, indicating don't care bits. When you
write to a register, you may set or clear these bits without effect.
SCXI-1160 Registers
The SCXI-1160 is a class II module. It has four registers and an address handler. The Module
ID Register is a 4-byte, read-only register that contains the Module ID number of the
SCXI-1160. The Data Register is a 32-bit, write-only register that controls the relay states on the
SCXI-1160. The Status Register is a 1-bit, read-only register that indicates the state of the relays
as either switching or finished switching. The Parking Register is a dummy register located at
address FFFF. The Address Handler is the register that contains the address of the register to be
read from or written to, and is a write-only register.
Address Handler
You must write to the Address Handler at the beginning of each write or read from the
SCXI-1160. Write the address of the register of interest to this handler, which in turn enables the
register of interest. The Address Handler is two bytes long and contains the address of the
register to be read from or written to. The Address Handler is selected when SS* is asserted low
and D*/A indicates an address transfer (D*/A is high). At this time, the address is shifted in the
Address Handler Register, MSB first. Table 4-1 contains a list of register addresses.